GIFT  OF 


UNIVERSITY    OF    CALIFORNIA    PUBLICATIONS 

BULLETIN   OF  THE    DEPARTMENT  OF 

GEOLOGY 

Vol.  8,  No.  6,  pp.  61-180,  pis.  6-18  Issued^  13,  1914 


FAUNA  OF  THE  MARTINEZ  EOCENE  OF 
CALIFORNIA 


BY 


ROY  ERNEST  DICKERSON 


esis  tied    in 

i    if 

lifornia. 


UNIVERSITY  OF  CALIFORNIA  PRESS 
BERKELEY 


UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 

NOTE. — The  University  of  California  Publications  are  offered  in  exchange  for  the  publi- 
cations of  learned  societies  and  institutions,  universities  and  libraries.  Complete  lists  of 
all  the  publications  of  the  University  will  be  sent  upon  request.  For  sample  copies,  lists  of 
publications  and  other  information,  address  the  Manager  of  the  University  Press,  Berkeley, 
California,  U.  S.  A.  All  matter  sent  in  exchange  should  be  addressed  to  The  Exchange 
Department,  University  Library,  Berkeley,  California,  U.  S.  A. 

OTTO  HARRASSOWITZ  K.  FRIEDLAENDER  &  SOHN 

LEIPZIG  BERLIN 

Agent  for  the  series  in  American  Arch-  Agent  for  the  series  in  American  Arch- 
aeology and  Ethnology,  Classical  Philology,  aeology  and  Ethnology,  Agricultural  Sciences, 
Economics,  Education,  History,  Modern  Botany,  Geology,  Mathematics,  Pathology, 
Philology,  Philosophy,  Psychology.  Physiology,  Zoology,  and  Memoirs. 

Geology. — ANDREW  C.  LAWSON  and  JOHN  C.  MERRIAM,  Editors.     Price  per  volume,  $3.50. 
Volumes  I  (pp.  435),  II  (pp.  450),  JII   (pp.  475),  IV   (pp.  462),  V   (pp.  448), 
VI  (pp.  454),  and  VII  (pp.  500),  completed.     Vol.  VIII  in  progiv 
Cited  as  Univ.  Calif.  Publ.  Bull.  Dept.  Geol. 

Volume  1,  1893-1896,  435  pp.,  with  18  plates,  price  $3,50 

Volume  2,  1896-1902,  450  pp.,  with  17  plates  and  1  map,  price  $3.50 

Volume  3,  1902-1904,  482  pp.,  with  51  plates,  price  $3.50 

A  list  of  the  titles  in  volumes  1,  2  and  3  will  be  sent  upon  request. 

VOLUME  4. 

1.  The  Geology  of  the  Upper  Begion  of  the  Main  Walker  Eiver,  Nevada,  by  Dwight 

T.  Smith 30c 

2.  A  Primitive  Ichthyosaurian  Limb  from  the  Middle  Triassie  of  Nevada,  by  John 

C.   Merriam   lOc 

3.  Geological  Section  of  the  Coast  Eanges  North  of  the  Bay  of  San  Francisco,  by 

V.  C.  Osmont  40c 

4.  Areas  of  the  California  Neocene,  by  Vance  C.  Osmont 15c 

5.  Contribution  to  the  Palaeontology  of  the  Martinez  Group,  by  Charles  E.  Weaver  20c 

6.  New  or  Imperfectly  Known  Eodents  and  Ungulates  from  the  John  Day  Series,  by 

William  J.  Sinclair  25c 

7.  New  Mammalia  from  the  Quarternary  Caves  of  California,  by  William  J.  Sinclair     25c 

8.  Preptoceras,  a  New  Ungulate  from  the  Samwel  Cave,  California,  by  Eustace  L. 

Furlong     lOc 

9.  A  New  Sabre-tooth  from  California,  by  John  C.  Merriam  5c 

10.  The  Structure  and  Genesis  of  the  Comstock  Lode,  by  John  A.  Eeid 15c 

11.  The  Differential  Thermal  Conductivities  of  Certain  Schists,  by  Paul  Thelen 25c 

12.  Sketch  of  the  Geology  of  Mineral  King,  California,  by  A.  Knopf  and  P.  Thelen 35c 

13.  Cold  Water  Bc:t  Along  the  West  Coast  of  the  United  States,  by  Euliff  S.  Holway  25c 

14.  The  Copper  Deposits  cf   the   Itotinson   Mining  District,   Nevada,   by  Andrew   C. 

Lawson 50c 

15.  I.  Contribution  ta.  the  Classification  of  the  Amphiboles. 

II.  On  Some  Glaucophane  Schlct3,  Syenites,  etc.,  by  G.  Murgoci 35c 

16.  The  Geomorphic  Features  of  the  Middle  Kern,  by  Andrew  C.  Lawson 15c 

17.  Notes  on  the  Foothill  Copper  Belt  of  the  Sierra  Nevada,  by  A.  Knopf. 

18.  An  Alteration  of  Coast  Eange  Serpentine,  by  A.  Knopf. 

Nos.  17  and  18  in  one  cover -< 15e 

19.  The  Geomorphogeny  of  the  Tehachapi  Valley  System,  by  Andrew  C.  Lawson 35c 

VOLUME  5. 

1.  Carnivora  from  the  Tertiary   Formations  of  the  John  Day   Eegion,  by  John  C. 

Merriam     .'. 60c 

2.  Some   Edentate-like  Eemains  from  the  Mascall   Beds  of  Oregon,  by  William  J. 

Sinclair. 

3.  Fossil  Mollusca  from  the  John  Day  and  Mascall  Beds  of  Oregon,  by  Eobert  E.  C. 

Stearns. 

os.  2  and  3  in  one  cover 15c 

4.  New  Cestraciont  Teeth  from  the  West  American  Triassie,  by  Edna  M.  Wemple lOc 

5.  Preliminary  Note  on  a  New  Marine  Eeptile  from  the  Middle  Triassie  of  Nevada, 

by  John  C.  Merriam 10e 


UNIVERSITY    OF    CALIFORNIA    PUBLICATIONS 

BULLETIN    OF  THE    DEPARTMENT  OF 

GEOLOGY 

Vol.  8,  No.  6,  pp.  61-180,  pis.  6-18  Issued  May  13,  1914 


FAUNA  OF  THE  MARTINEZ  EOCENE  OF 
CALIFORNIA 


BY 

ROY  ERNEST  DICKERSON 


CONTENTS 

PAGE 

Introduction    64 

Review  of  the  Literature  64 

Areal  Distribution  of  the  Martinez  in  California  69 

Principal  Localities  69 

Distribution  of  the  Martinez  Compared  with  that  of  the  Tejon 69 

Description  of  the  Typical  Martinez  Sections  in  California  71 

Lower  and  Middle  Zones  of  Martinez  North  of  Mount  Diablo  71 

Fauna  of  the  Meretrix  dalli  Zone  71 

Fauna  of  the  Trochocyathus  zitteli  Zone  74 

Martinez  and  Tejon  South  of  Mount  Diablo  77 

Type  Locality  of  the  Martinez  79 

Stratigraphy  79 

Relations  to  the  Martinez  at  Selby  Smelter  81 

Faunal   Zones   81 

Martinez  at  Benicia  87 

Martinez  at  Selby  Smelter 88 

Martinez  at  Lower  Lake,  Lake  County,  California  89 

Transitionary  Beds  of  Gabb  89 

Stanton's  Discussion  of  the  Fauna  91 

Stratigraphy  and  Structure  92 

Fauna  of  Martinez  at  Lower  Lake  95 

Martinez  of  San  Mateo  County  99 

Eocene(?)  of  the  Santa  Cruz  Quadrangle  102 

Summary  of  Martinez  Stratigraphy  103 


•«'«,•«  4          •   »    I        .  . 

I    »    ••   £    *    '     *t     r«    -          •      •» 
•    •  .     •       *  *   *.     .         •     * 

•*>•*••>•>•  i       •.,•»*.-•'«• 

62  University  of  California  Publications  in  Geology          [VOL.  8 

PAGE 

Summary  of  Martinez  Fauna  106 

Suggestion  of  Fauna  as  to  Climate  during  Martinez  Time  Ill 

Eelationship  of  Chico  and  Martinez  Faunas  112 

Faunal  Eelationship  of  the  Martinez  to  the  Tejon 112 

Comparison  of  Uppermost  Martinez  and  Lowermost  Tejon  114 

Time-Interval  between  Deposition  of  Martinez  and  Tejon  117 

Correlation  of  Martinez  with  Eocene  of  the  Atlantic  and  Gulf  States  117 

Genera  Common  to  Martinez  and  Midway 118 

General  Present  in  Midway  but  Absent  in  Martinez  119 

Proposed  Correlation  119 

Summary   120 

Descriptions  of  Species , 120 

Anthozoa   120 

Flabellum,  sp 120 

Paracyathus(  ?),  sp 120 

Echinoidea  121 

Cidaris(f),  sp.,  a 121 

Cidaris,  sp.,  c 121 

Schizaster  lecontei  Merriam  121 

Bryozoa    122 

Membranopora(  ?),  sp 122 

Brachiopoda    122 

Ehynconella(  ?),  sp 122 

Pelecypoda  123 

Leda  packardi,  n.  sp 123 

Leda  milleri,  n.  sp 123 

Yoldia  gesteri,  n.  sp 124 

Yoldia  powersi,  n.  sp 124 

Pinna  barrowsi,  n.  sp 125 

Lima(?)  claytonensis,  n.  sp 126 

Lima(?)  haseltinei,  n.  sp 126 

Ostrea  buwaldana,  n.  sp 127 

Ostrea  weaveri,  n.  sp 127 

Pecten   (Chalamys?),  sp 128 

Modiolus  bakeri,  n.  sp 128 

Cuspidaria  hannibali,  n.  sp 129 

Crassatellites  studleyi,  n.  sp 129 

Crassatellites  stewartvillensis,  n.  sp 130 

Crassatellites  claytonensis,  n.  sp 131 

Cardita  veneriformis  Gabb  131 

Phacoides  quadrata,  n.  sp 131 

Phacoides  muirensis,  n.  sp 132 

Phacoides  diaboli,  n.  sp 132 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          63 

PAGE 

Dosinia(?)  lawsoni,  n.  sp 133 

Venus( f ),  sp ...^...~ 133 

Meretrix  stantoni,  n.  sp 134 

Meretrix  dalli,  n.  sp 135 

Meretrix,  sp 135 

Macrocallista(?)  packi,  n.  sp 136 

Paphia(?)  clarki,  n.  sp 136 

Tellina  herndonensis,  n.  sp 136 

Tellina  packardi,  n.  sp 137 

Tellina  perrini,  n.  sp 137 

Tellina  kewi,  n.  sp 138 

Psammobia(?)  cylindrica,  n.  sp 139 

Spisula(?)  weaveri,  n.  sp.  Packard  139 

Martesia(?),  sp 140 

Gastropoda  140 

Acmaea  martinezensis,  n.  sp 140 

Fissurella(?)  behri,  n.  sp 141 

Nerita(?)  biangulata,  n.  sp 141 

Natica  (Gyrodes)  lineata,  n.  sp 141 

Amauropsis  martinezensis,  n.  sp 142 

Turritella  clarki,  n.  sp 142 

Cerithium,  sp 143 

Alaria,  sp 143 

Anchura  englishi,  n.  sp 144 

Anchura  gabbi,  n.  sp 144 

Seraphs  (?)  thompsoni,  n.  sp 144 

Ovula  martini,  n.  sp 145 

Tritonium  buwaldi,  n.  sp 145 

Tritonium  martinezensis,  n.  sp 146 

Hemifusus(?)  waringi,  n.  sp 146 

Fusus  dumblei,  n.  sp 146 

Olivella  claytonensis,  n.  sp 147 

Turris  louderbaeki,  n.  sp 147 

Surcula  merriami,  n.  sp 148 

Surcula  fairbanksi,  n.  sp 148 

Surcula  (Surculites)  andersoni,  n.  sp 149 

Surcula,  sp 149 

Cephalopoda  150 

Hercoglossa  merriami,  n.  sp 150 

Nautilus  stephensoni,  n.  sp 150 

Previously  Described  Martinez  Species  Ke-figured  151 

Appendix:  List  of  Localities ..  152 


64  University  of  California  Publications  in  Geology          [VOL.  8 


INTRODUCTION 

The  discovery  of  several  new  areas  of  Martinez  rocks  and  the  secur- 
ing of  large  additions  to  the  fauna  in  them  have  led  to  further  investi- 
gation of  the  stratigraphy  and  fauna  of  the  lower  Eocene  of  the  Pacific 
Coast.  That  the  Martinez  is  separated  from  the  Chico  (Cretaceous) 
below  and  from  the  Tejon  (upper  Eocene)  above  by  well-marked 
unconformities  are  the  principal  conclusions  from  stratigraphic 
studies.  Faunal  studies  prove  that  the  Martinez  fauna  of  approxi- 
mately two  hundred  species  is  quite  distinct  from  the  Chico  and  the 
Tejon  faunas.  The  great  increase  in  the  fauna  makes  correlation  with 
the  lowermost  Eocene  of  the  Gulf  and  Atlantic  states  more  certain. 
The  proposed  correlation  made  in  this  paper  fixes  a  portion  of  the 
Martinez  as  the  equivalent  of  the  lowermost  Eocene  of  the  Gulf 
States,  the  Midway,  and  the  rest  as  the  representative  of  an  earlier 
Eocene  time  than  has  been  recognized  elsewhere  in  the  United  States. 


REVIEW  OF  THE  LITERATURE 

W.  M.  Gabb1  first  used  the  term  Martinez  Group  to  describe  strata 
which  he  thought  were  transitional  between  the  Chico-Cretaceous  and 
his  Cretaceous  "B,"  the  Tejon  of  the  present  nomenclature.  Dr. 
T.  W.  Stanton2  next  investigated  this  group.  He  proved  that  a  portion 
of  the  Martinez  Group  of  Gabb  was  Chico  and  placed  the  upper  portion 
as  a  distinct  faunal  zone  of  the  Tejon,  designating  it  as  lower  Tejon. 

Dr.  Stanton 's  admirable  review  was  followed  by  a  short,  decisive 
paper  by  Merriam3  who  worked  at  the  type  locality.  Merriam 
described  the  conditions  at  the  type  locality  as  follows : 

In  the  following  discussion  the  name  Martinez  is  applied  to  that  portion 
of  Gabb's  Martinez  Group  which  remains,  after  the  removal  of  the  Chico- 
Cretaceous  element.  The  writer's  statements  are  based  on  observations,  extend- 
ing over  a  period  of  several  years,  made  in  the  typical  region  for  the  group, 
viz.,  that  adjacent  to  the  town  of  Martinez. 

In  the  hills  to  the  southwest  of  Martinez,  strata  of  unquestionable  Chico 
age,  containing  a  characteristic  fauna,  occur  over  a  considerable  area.  In  a 

1  Gabb,  W.  M.,  Kept.  Geol.  Surv.  of  California,  Palaeontology,  vol.  2,  p.  13  of 
preface,  1869. 

2  Stanton,  T.  W.,  The  Faunal  Relations  of  the  Eocene  and  Upper  Cretaceous 
on  the  Pacific  Coast,  17th  Ann.  Kept.  U.  S.  Geol.  Surv.,  pp.  1011-1060,  1895-6. 

s  Merriam,  J.  C.,  The  Geological  Relations  of  the  Martinez  Group  of  Cali- 
fornia at  the  Typical  Locality,  Jour,  of  Geology,  vol.  5,  pp.  767-775,  1897. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          65 

• 

fine  outcrop  of  compact  bluish  sandstone  occurring  on  the  west  side  of  Alhambra 
Valley,  and  near  the  top  of  the  Chico,  the  writer  found  an  abundance  of  fossils, 
characteristic  of  this  group.  .  .  .  From  this  point  to  the  east  and  west  the 
structure  of  the  strata  is  anticlinal,  showing  an  apparently  conformable  series 
up  as  far  as  the  Miocene  on  each  side. 

From  the  standpoint  of  stratigraphy,  one  would  hardly  be  disposed  to  find 
fault  with  Gabb  's  conception  of  the  Martinez,  since  in  this,  the  typical  locality, 
the  Chico,  Martinez,  and  Tejon  appear  everywhere  to  be  conformable,  while 
numerous  complications  of  the  stratigraphy  have  still  farther  increased  the 
difficulty  of  separating  these  three  groups  on  stratigraphic  grounds. 

Lithologically  there  are  some  differences  between  the  Martinez  and  the 
adjoining  formations,  the  most  important  of  which  are  the  slightly  different 
aspect  of  its  sandstones  and  the  frequent  presence  in  them  of  considerable 
quantities  of  glauconite.  The  sandstones  are  often  grayish,  differing  from  the 
yellowish  or  bluish  rocks  of  the  Chico  and  the  massive  white  to  dull  red  Tejon 
sandstones.  In  many  places  the  Martinez  contains  large  quantities  of  glauconite 
disseminated  evenly  through  the  sandstone  in  rounded  grains  of  considerable 
size.  Glauconite  does  not  seem  to  occur  at  all  in  the  Chico  but  may  possibly 
be  found  toward  the  base  of  the  true  Tejon.  The  truly  glauconitic  rocks  belong 
principally  to  the  Martinez. 

While  the  group  shows  little  which  would  serve  to  separate  it  strati- 
graphically  or  lithologically  from  the  over  and  underlying  formations,  its 
fauna,  on  which  Gabb  based  his  classification,  contains  numerous  elements 
throwing  light  on  its  geologic  relations.  Between  the  Chico-Cretaceous  and 
the  Miocene  there  are  two  distant  faunas  present,  viz.,  the  Martinez  (in  part) 
and  Tejon  of  Gabb,  or  the  Lower  and  Upper  Tejon  of  Mr.  Stanton.  As  other 
criteria  failed  to  separate  satisfactorily  the  Chico,  Martinez,  and  Tejon,  exten- 
sive fossil  collections  were  made  by  the  writer  at  all  possible  points. 

Merriam  then  discussed  collections  made  in  a  section  across  the 
strike  in  the  typical  Chico,  Martinez  and  Tejon,  suggested  the  exist- 
ence of  two  faunal  zones  in  the  Martinez,  and  described  the  palaeon- 
tology of  the  Martinez : 

The  faunas,  though  overlapping,  are  in  the  main  quite  distinct,  and  no 
great  difficulty  has  been  experienced  by  the  writer  in  separating  the  groups  on 
this  basis.  While  some  intermingling  of  species  exists,  it  is  not  greater  than 
we  should  expect  to  find  in  adjoining  groups  or  periods.  It  should  also  be 
observed  that  the  beds  with  a  Tejon-like  Martinez  fauna  and  those  containing 
an  assemblage  of  characteristic  Tejon  forms  are  comparatively  close  together. 
The  change  from  one  fauna  to  the  other  may  possibly  have  taken  place  in  a 
short  time  by  migration,  but  we  can  not  assert  positively  as  yet  that  the 
apparent  conformity  of  the  beds  is  a  real  one;  sedimentation  may  have  been 
interrupted  between  the  times  of  deposition  of  the  two  groups.  It  is,  at  any 
rate,  quite  clear  that  the  two  sets  of  strata,  or  two  faunas,  while  belonging 
perhaps  to  the  same  series,  represent  different  periods  in  the  geological  history 
of  California,  periods  quite  as  distinct,  so  far  as  faunal  evidence  is  concerned, 
as  the  Miocene  and  Pliocene,  or  the  Pliocene  and  Quaternary.  The  upper 
division  of  this  series  has  already,  on  the  grounds  of  its  characteristic  fauna, 
been  named  the  Tejon.  To  a  mixed  group  of  rocks,  to  which  the  fauna  here 
called  the  Martinez  gave  individuality,  the  name  Martinez  group  was  applied 


66  University  of  California  Publications  in  Geology          [VOL.  8 

by  Gabb.  It  seems  desirable,  after  having  cut  out  the  Chico  portion  of  Gabb's 
Martinez  which  was  probably  not  the  one  on  which  he  based  the  group,  to 
apply  the  name  used  by  him  to  the  distinct  fauna  or  group  which  remains. 
As  to  the  nomenclature  of  the  supposedly  conformable  series,  including  the 
Martinez  and  Tejon,  it  seems  best  to  apply  to  it  for  the  present  the  term 
Martinez-Tejon  series,  though  future  convenience  may  demand  a  special  series 
name.  To  apply  the  name  Tejon  to  the  whole  series  would  be  to  modify  con- 
siderably the  meaning  of  this  term  as  used  originally,  and  would  have  besides 
the  fault  of  taking  the  name  from  a  smaller  division  to  apply  it  to  a  larger, 
leaving  the  first  to  be  virtually  renamed. 

He  then  closed  with  a  definition  of  the  Martinez  Group  as  follows : 

The  Martinez  group,  comprising  in  the  typical  locality  between  one  and 
two  thousand  feet  of  sandstones,  shales,  and  glauconitic  sands,  forms  the 
lower  part  of  a  presumably  conformable  series,  the  upper  portion  of  which  is 
formed  by  the  Tejon.  It  contains  a  known  fauna  of  over  sixty  species,  of 
which  the  greater  portion  is  peculiar  to  itself.  A  number  of  its  species  range 
up  into  the  Tejon  and  a  very  few  long-lived  forms  are  known  to  occur  also 
in  the  Chico.  Since  the  Martinez  and  Chico  are  faunally  only  distantly 
related,  it  is  probable  that  an  unconformity  exists  between  them.  Though 
satisfactory  correlation  of  California  formations  with  the  subdivisions  of  the 
standard  geological  scale  can  be  accomplished  only  when  the  local  scale  is  fully 
worked  out,  we  may,  for  the  present  at  least,  accept  Mr.  Stanton's  correlation 
of  the  Martinez  with  a  portion  of  the  Eocene. 

In  a  general  correlation  paper,  Dall4  places  both  the  Martinez  and 
the  Tejon  as  correlative  of  the  Midway  stage  of  the  southeastern 
United  States  and  the  Cernaysian  of  Europe. 

Lawson5  in  describing  a  section  in  the  neighborhood  of  the  type 
locality  of  the  Martinez  substitutes  the  name  "Karquinez  series"  for 
that  of  Merriam's  Martinez-Tejon  series,  and  estimates  their  combined 
thickness  as  4300  feet. 

In  a  paper  entitled  "  Contribution  to  the  Palaeontology  of  the 
Martinez  Group,"  Weaver6  carefully  described  the  distribution  of  the 
Martinez,  its  stratigraphic  relations,  recognized  two  faunal  zones, 
correlated  it  with  the  Midway  of  the  Gulf  States  and  the  Aquia  stage 
of  Maryland  and  Virginia,  and  described  several  new  species.  In 
summary  he  said : 

....  the  Martinez  represents  a  distinct  division  of  time  in  the  geological 
history  of  California.  It  contains  a  fauna  distinct  from  both  the  Chico  and 


*  Dall,  W.  H.,  A  Table  of  the  North  American  Tertiary  Horizons  correlated 
with  one  another  and  with  those  of  western  Europe,  18th  Ann.  Eept.  U.  S.  Geol. 
Surv.,  part  2,  pp.  327-348,  1898. 

s  Lawson,  A.  C.,  A  Geological  Section  of  the  Middle  Coast  Eanges  of  Cali- 
fornia, Science,  n.s.,  vol.  15,  p.  416,  1902. 

«  Weaver,  C.  E.,  Contribution  to  the  Palaeontology  of  the  Martinez  Group, 
Univ.  Calif.  Publ.  Bull.  Dept.  Geol.,  vol.  4,  pp.  101-123,  1905. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  Calif  ornia          67 

the  Tejon.  On  the  average  it  is  composed  of  about  two  thousand  feet  of 
thick-bedded  sandstones  and  conglomerates.  Its  geographical  extent  as  at 
present  known  is  confined  to  southern  Lake  County  and  a  belt  extending  north 
and  south  across  Carquinez  Strait.  Its  position  in  the  geologj,caj_  scale  seems 
to  correspond  most  closely  to  a  portion  or  all  of  the  lower  quarter  of  the 
Eocene. 

Arnold7  gave  a  list  of  fossils  compiled  from  the  papers  of  Stanton, 
Merriam,  and  Weaver,  added  a  few  new  species  obtained  "from  a 
locality  of  doubtful  Martinez  age,"  and  described  Pecten  proavus 
from  this  locality  in  Santa  Cruz  County.  He  mentioned  Rock  Creek, 
Los  Angeles  County  as  a  Martinez  locality.  In  a  later  paper8  he 
described  the  Santa  Cruz  locality,  gave  a  list  of  fossils  obtained  from 
it  and  described  Cidaris  merriami,  Semele  gayi,  Tritonium  newsomi, 
Hipponyx  carpenteri,  Patella  mateoensis,  and  Fissurella  perrini.  He 
described  the  Martinez  (?)  of  the  Santa  Cruz  Quadrangle  as  follows : 

The  diabase  dike  exposed  north  of  the  headwaters  of  Pescadero  Creek  has 
brought  up  considerable  inclusions  of  impure  limestone  which,  from  the  fossils 
found  in  them,  appear  to  be  of  Eocene  age.  Obviously  the  stratigraphic  rela- 
tions of  this  great  limestone  inclusion  are  unknown,  but  the  fossils  indicate 
its  Eocene  age  and  that  it  probably  belongs  in  the  lower  part  of  the  formation. 
The  following  fauna  occurs  in  this  limestone: 

LIST  OF  LOWER  EOCENE  FOSSILS  FROM  THE  SANTA  CRUZ  QUADRANGLE 

ECHINOIDEA 

Cidaris  merriami,  new  species 

BRACHIOPODA 

Terebratalia,  new  species,  m.  Terebratulina  tejonensis  Stanton 

Terebratalia,  new  species,  p. 

PELECYPODA 
Pecten  proavus  Arnold  Semele  gayi  Arnold 

GASTROPODA 

Chlorostoma,  new  species,  c.  Patella,  new  species,  b. 

Cylindrites  ~brevis(?)  Gabb  Patella  mateoensis  Arnold 

Fissurella  perrini  Arnold  Thylacodes,  new  species,  w. 

Hipponyx  carpenteri  Arnold  Tritonium  newsomi  Arnold 
Odostomia,  new  species,  b. 


7  Arnold,  Kalph,  The  Tertiary  and  Quaternary  Pectens  of  California,  Profes- 
sional Paper  no.  47,  U.  S.  Geological  Survey,  pp.  11-12,  1906. 

s  Arnold,  Ealph,  Descriptions  of  New  Cretaceous  and  Tertiary  Fossils  from 
the  Santa  Cruz  Mountains,  California,  Proceedings  of  the  United  States  National 
Museum,  vol.  34,  no.  1617,  pp.  347,  359-363,  August,  1908. 


68  University  of  California  Publications  in  Geology          [VOL.  8 

A  short  description  of  these  same  beds  is  also  given  in  the  Santa 
Cruz  folio  :9 

The  diabase  exposed  north  of  the  headwaters  of  Pescadero  Creek  has 
brought  up  some  considerable  inclusions  of  impure  limestone  which,  from  the 
fossils  found  in  them,  appear  to  be  of  Eocene  age.  The  limestone  is  light  brown 
in  color,  usually  rather  soft  except  where  silicification  has  begun,  and  appears 
to  be  made  up  of  broken  marine  shells,  a  little  argillaceous  material,  and  small 
fragments  of  what  may  be  tuff.  The  thickness  of  the  limestone  is  nowhere  more 
than  100  or  200  feet. 

On  Langley  and  Mindego  Hills,  two  and  a  half  miles  northeast  and  south- 
east, respectively,  of  the  village  of  La  Honda,  are  two  other  small  areas  of 
calcareous  sandstone,  supposed  to  be  of  the  same  age  as  that  exposed  north 
of  the  headwaters  of  Pescadero  Creek. 

Fossils — The  fauna  of  the  limestone  in  the  Pescadero  Creek  exposure  above 
referred  to  is  different  from  that  of  any  of  the  other  known  formations  of 
California.  Some  of  its  species  as  Patella  mateoensis  Arnold,  Fissurella  perrini 
Arnold,  Tritonium  newsomi  Arnold,  and  Pecten  proavus  Arnold,  are  closely 
allied  to  Chico  (Cretaceous)  forms,  while  Ostrea  cf.  idriaensis  Gabb  is  found  only 
in  the  Tejon  (middle  Eocene),  and  Terebratulina  tejonensis  Stanton  only  in  the 
Martinez  (lower  Eocene).  In  view  of  the  affinities  of  the  above  species  and 
also  of  the  several  new  ones,  it  appears  probable  that  the  fauna  represents 
either  a  new  horizon  of  the  lower  Eocene  or  a  local  development  of  the 
Martinez  (lower  Eocene)  fauna. 

These  beds  do  not  appear  to  be  of  Martinez  age  to  the  writer. 

Dickerson10  in  a  short  paper  described  unconformities  between  the 
Martinez  and  Chico  and  between  the  Tejon  and  Martinez,  and  gave 
partial  lists  of  fossils  collected  from  a  section  across  the  strike  from 
the  Chico,  Martinez  and  Tejon.  These  lists  show  a  very  marked 
difference  between  the  faunas  of  the  Chico,  Martinez  and  Tejon. 

In  a  recent  number  of  the  Journal  of  Geology,  Durable11  described 
an  unconformity  between  the  Cretaceous  and  beds  which  he  supposed 
to  be  of  Martinez  age.  Later  work  by  Taff,  Gester,  Parsons,  and 
Dickerson  has  shown  that  the  so-called  Martinez  is  Tejon. 


»  Branner  J.  C.,  Newsom,  J.  E.,  Arnold,  E.,  Santa  Cruz  Folio,  No.  165,  U.  S. 
Geological  Survey,  p.  3,  April,  1908. 

10  Dickerson,  Eoy  E.,  The  Stratigraphy  and  Faunal  Relations  of  the  Martinez 
Formation  to  the  Chico  and  Tejon  North  of  Mount  Diablo,  Univ.  Calif.  Publ. 
Bull.  Dept.  Geol.,  vol.  4,  pp.  173-177,  1911. 

11  Durable,  E.  T.,  Notes  on  Tertiary  Deposits  near  Coalinga  Oil  Field  and 
their  Stratigraphic  Eelations  with  Upper  Cretaceous,  Jour.  Geol.,  vol.  20,  pp. 
28-37,  1912. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          69 

AEEAL  DISTRIBUTION  OF  THE  MARTINEZ  IN  CALIFORNIA 

PRINCIPAL  LOCALITIES 

The  most  northerly  occurrence  of  Martinez  thus  far  reported  is 
near  the  town  of  Lower  Lake,  in  Lake  County.  Martinez  strata  occur 
in  the  Napa  Quadrangle  four  miles  northwest  of  Suisun,  where  Gabb12 
found  fine  specimens  of  Turrit ella  pachecoensis  and  Meretrix(f) 
fragilis,  and  near  Benicia.  Across  the  Carquinez  Strait  from  Benicia 
is  the  type  locality  of  the  Martinez  near  the  town  of  that  name.  In 
1909,  R.  W.  Pack  and  G.  E.  Gester  recognized  a  small  area  of  Martinez 
on  Carquinez  Strait  at  Selby  Station.  North  of  Mount  Diablo  another 
area  occurs,  and  a  very  small  but  interesting  locality  was  found  south- 
west of  Mount  Diablo  by  the  1911  University  of  California  Summer 
Session  class  in  palaeontology.  Beds  of  Martinez  age  make  up  a 
portion  of  the  strata  at  San  Pedro  Point,  in  San  Mateo  County. 
Dumble13  reported  Martinez  north  of  Coalinga,  but  later  work  has 
shown  that  these  beds  are  a  phase  of  the  Tejon. 

A  typical  collection  of  Martinez  fossils  was  made  by  the  1910 
Stanford  University  class  in  geology  forty  miles  northwest  of  Los 
Angeles  in  the  Calabassas  Quadrangle.  Arnold14  reported  Martinez  at 
Rock  Creek,  Los  Angeles  County.  The  Martinez  was  recognized  by 
the  1913  University  of  California  Summer  Session  class  in  palaeon- 
tology in  the  Santa  Ana  Mountains.  No  positive  evidence  of  Martinez 
south  of  this  last  point  is  known,  but  Stanton15  reports  Glycimeris 
veatchii  var.  major  from  Point  Loma  near  San  Diego.  None  of  the 
collections  from  this  locality  which  the  writer  has  examined  have  con- 
tained any  typical  Martinez  forms;  all  appear  to  be  Tejon  or  Chico. 

DISTRIBUTION  OF  THE  MARTINEZ  COMPARED  WITH  THAT  OF  THE  TEJON 

Some  interesting  relations  between  the  Martinez  and  the  Tejon  are 
brought  out  when  their  distribution  is  studied.  (See  fig.  1.)  In 
certain  localities  the  Martinez  and  Tejon  occur  together,  but  in  other 


i^  Gabb.,  W.  M.,  Kept.  Geol.  Surv.  of  California,  Palaeontology,  vol.  2,  p.  135, 
1869. 

is  Dumble,  E.  T.,  Notes  on  Tertiary  Deposits  near  Coalinga  Oil  Field  and 
their  Stratigraphic  Eelations  with  Upper  Cretaceous,  Jour.  Geol.,  vol.  20,  pp. 
28-37,  1912. 

i*  Arnold,  E.,  Tertiary  and  Quaternary  Pectens  of  California,  Professional 
Paper  no.  47,  U.  S.  Geological  Survey,  p.  11,  1906. 

is  Stanton,  T.  W.,  The  Faunal  Eelations  of  the  Eocene  and  Upper  Cretaceous 
on  the  Pacific  Coast,  17th  Ann.  Eept.  U.  S.  Geol.  Surv.,  p.  1040,  1895-6. 


70  University  of  California  Publications  in  Geology          [VOL.  8 

places  the  one  occurs  without  the  other.  They  are  associated  at 
Lower  Lake  in  Lake  County,  but  no  Martinez  occurs  at  the  Marys- 
ville  Buttes  in  Colusa  County  where  uppermost  Tejon  is  found.  The 
Tejon  of  Merced  Falls  rests  directly  upon  rocks  of  Jurassic  age.  Both 
are  found  at  Benicia,  Martinez,  and  north  of  Mount  Diablo,  but  on 
the  south  side  of  Mount  Diablo,  the  Tejon  for  the  most  part  rests 
directly  upon  the  Chico.  At  San  Pedro  Point,  San  Mateo  County, 
Martinez  without  Tejon  is  found.  At  the  type  locality  of  the  Tejon 
on  the  Canada  de  las  Uvas  the  upper  Eocene  rests  upon  the  basement 
complex  of  the  Tehachapi  Mountains,  and  no  Martinez  appears  to  be 
present  at  the  southern  end  of  the  San  Joaquin  Valley.  However, 
Martinez  does  occur  on  the  seaward  side  of  the  ranges  along  the  coast 
thirty  miles  south  of  this  same  latitude  in  the  Calabasas  Quadrangle. 
The  Tejon  at  San  Diego  overlies  the  Chico.  Fairbanks10  mapped  no 
Eocene  in  the  San  Luis  Quadrangle.  South  of  this  quadrangle  great 
thicknesses  of  Eocene  strata  were  reported  by  Eldridge  and  Arnold17 
in  the  Santa  Clara  Valley.  These  beds  were  called  the  Topatopa 
formation.  No  attempt  was  made  to  differentiate  the  upper  and  lower 
portions  of  the  "formation." 

At  least  three  marked  epirogenic  movements  occurred  during 
Eocene  time:  (1)  a  subsidence  of  the  coast  during  which  the  Martinez 
sediments  were  deposited,  (2)  an  uplift  during  which  large  portions 
of  Martinez  sediments  were  removed,  (3)  a  subsidence  during  which 
the  Tejon  sediments  were  deposited.  That  the  sea  during  the  first 
subsidence  did  not  extend  so  far  inland  as  during  the  second  appears 
to  be  true,  and  deposition  by  a  transgressing  sea  might  account  for 
the  occurrence  of  Tejon  at  Merced  Falls  and  the  Marysville  Buttes 
unassociated  with  Martinez  if  it  were  not  for  a  widespread  uncon- 
formity between  these  two  groups.  Tejon  sediments  2600  feet  thick 
south  of  Mount  Diablo  rest  unconformably  upon  Chico,  whereas  at 
least  700  feet  of  Martinez  is  found  between  the  groups  north  of  the 
mountain.  Unconformity  between  the  two  groups  and  a  more  widely 
spread  sea  during  Tejon  time  account  for  the  difference  in  distribution 
of  the  Martinez  and  Tejon  in  California. 


16  Fairbanks,  H.  W.,  San  Luis  Folio,  no.  101,  U.  S.  Geological  Survey,  p.  3, 
1904. 

i?  Eldridge,  G.  H.,  and  Arnold,  E.,  The  Santa  Clara  Valley,  Puente  Hills  and 
Los  Angeles  Oil  District,  Southern  California,  Bull.  no.  309,  U.  S.  Geological 
Survey,  pp.  5-7,  1907. 


Fig.  1.     Map  of  California  showing  probable  extent  of  the  Tejon  and  Martinez  Seas, 
vhich  in  general  is  the  more  easterly  marks  the  maximum  inland  extension  of  the  Tejon  Se 
)ther  line  indicates  the  probable  easterly  limit  of  the  Martinez  Sea. 

1,  Tejon  of  Round  Valley,  Mendocino  County;   2,  Tejon  near    Oroville;    3,    Tejon    of    Marysville    Buttes; 
louth  of  Merced  River  Canon;   5,  Tejon  of  the  Tehachapi  Mountains;   6,  Martinez  of  Rock  Creek;   7,  Tejon  o 
!ounty;  8,  Tejon  and  Martinez  at  Clear  Lake;  9,  Martinez  north  of  Suisun ;  10,  Martinez  and  Tejon  at  Benic 
>cality  of  Martinez;    12,    Martinez   and  Tejon   north  of   Mount  Diablo;    13,   Martinez  and  Tejon   south  of  Me 
4,  Martinez  of  San  Pedro  Point,   San  Mateo  County;    15,   Tejon  at  New  Idria;   16,  Tejon  at  Coalinga  Distric 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          71 

DESCRIPTIONS    OF    THE    TYPICAL    MARTINEZ    SECTIONS 

IN  CALIFORNIA       • 

LOWER  AND  MIDDLE  ZONES  OF  MARTINEZ  NORTH  OF  MOUNT  DIABLO 

The  stratigraphy  and  the  faunal  relations  of  the  Martinez  to  the 
Chico  and  Tejon  have  already  been  fully  discussed  in  a  former 
paper.18  The  zonal  relations  of  the  Martinez  in  this  area  have  not 
been  described.  In  the  Martinez  area  four  miles  north  of  Mount 
Diablo  we  have  a  lower  section  which  has  yielded  the  most  abundant 
fauna  of  any  Martinez  locality,  over  eighty  species  having  been  found 
in  the  lowermost  beds  alone.  Abundantly  fossiliferous,  distinctly 
bedded  outcrops  extending  for  the  entire  length  of  the  east-west  four- 
mile  strip  have  enabled  the  writer  to  be  sure  of  the  stratigraphic 
position  of  the  various  fossil  localities.  A  north-south  cross-section 
examined  a  mile  south  of  Stewartville  is,  in  descending  order,  as 
follows : 

(5)   Gray-green  shales,  250-300  feet. 

(4)   Gray-green,  glauconitic  sandstone,  50  feet. 

(3)  Fine-grained,  hard,  gray  sandstone,  200  feet. 

(2)   Shales  and  argillaceous  sandstones,  100  feet. 

(1)  Brown,  conglomeratic,  lower  sandstone,  50-100  feet. 

Total,  650-750  feet. 
(See  figure  2.) 

A  similar  section  was  examined  at  the  head  of  Oil  Creek,  two  miles 
west  of  this  line.  The  principal  fossil  localities  are  limited  to  the 
lower  bed  and  the  gray-green  glauconitic  sandstone  four  hundred  feet 
above  the  base.  The  accompanying  map  shows  these  localities  (see 
fig.  3).  The  lower  bed  yielded  a  fauna  in  which  one  of  the  most 
abundant  forms  was  Meretrix  dalli,  n.  sp. 

FAUNA  OF  THE  MERETRIX  DALLI  ZONE 

Large  collections  from  the  lowermost  beds  have  been  made  by 
J.  R.  Powers,  B.  L.  Clark,  William  Kew  and  the  writer  in  the  past 
three  years.  Below  is  a  complete  list  of  the  fauna  obtained  from 
these  beds: 


is  Dickerson,  Roy  E.,  Univ.  Calif.  Publ.  Bull.  Dept.  Geol.,  vol.  6,  pp.  173-177, 
1911. 


72 


University  of  California  Publications  in  Geology          [VOL.  8 


.o 


~ 

o 

•a 

03 


.3   fl 

•e.2 


Is 

^3  «H 

Oco 

<H    03 
O    M 


bfl 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California  73 
FAUNA  OF  THE  MERETRIX  DALLI  ZONE  IN  THE  MARTINEZ  NORTH  OF  MOUNT  DIABLO 

Loc.  Loc.          Loc.          Loc. 

1745  1556          1743          1557 

Flabellum  remondianum  Gabb  x      __  _X             x 

Cidaris,  sp.,  a  

Cidaris,  sp.,  d  x 

Schizaster  lecontei  Merriam  ....             x 

Terebratula(?),  sp : 

Terebratulina  tejonensis  Stanton  ....             X 

Cardium  cooperi  Gabb  ....             x             x 

Cardium,  sp 

Cardita   veneriformis    Gabb    x 

Cucullaea    mathewsonii    Gabb    x             x             x 

Corbula,  sp x           ....             x 

Crassatellites  unioides  (Stanton)  

Cuspidaria  dolabraeformis  (Gabb)   x 

Glycimeris  veatchii,  var.  major  (Stanton)  x 

Lima  cf.  multiradiata  Gabb  x 

Leda  gabbi  Conrad  x             x             x 

Leda  packardi,  n.  sp x  ....             x 

Leda  milleri,  n.  sp x 

Modiolus  bakeri,  n.  sp x 

Modiolus  ornatus   (Gabb)   x 

Mytilus  cf.  ascia  Gabb  x 

Meretrix  stantoni,  n.  sp x           ....             X 

Meretrix  dalli,  n.  sp ....             x 

Nucula  (Acila),  sp x           ....             x 

Ostrea,  sp x 

Paphia(?)  clarki,  n.  sp x             x             x 

Phacoides  turner!  (Stanton) x  ....           ....             X 

Pecten,  sp.,  a  x 

Pholadomya  nasuta  Gabb  x             x 

Solen,  sp ....             x 

Solen  stantoni  Weaver  : ....             x 

Spisula(?)  weaveri,  n.  sp.,  Packard  x 

Tapes,  sp.,  a  ....           ....             x 

Tapes(?)  quadrata  Gabb  

Tellina  undulifera  Gabb x             x 

Tellina  cf.  aequalis  Gabb  x 

Tellina,  sp.,  a  ....           ....             x 

Teredo,  sp x             x 

Zirphaea(f),  sp ....             x 

Dentalium,   sp x 

Dentalium  cooperi  Gabb  

Amauropsis  martinezensis,  n.  sp x 

Anchura,  sp X 

Ampullina  striata  Gabb  ....             x 

Brachysphingus  liratus  Gabb  ....           ....             x 

Cylichna  costata  Gabb  x             x             x 

Fusus  cf.  martinez  Gabb  x  .  .... 

Fusus(?),  sp x 


74  University  of  California  Publications  in  Geology          [VOL.  8 

FAUNA  OF  THE  MERETRIX  DALLI  ZONE  IN  THE  MARTINEZ  NORTH  OF  MOUNT  DIABLO 

(Continued) 


Loc.          Loc. 

Loc. 

Loc. 

1745         1556 

1743 

1557 

Fusus,  sp  

X 

.... 

.... 

Galerus  excentricus  Gabb  

X 

Heteroterma  striata  Stanton  

X 

.... 

Lunatia  hornii  Gabb  

X 

.... 



Natica,  sp.,  a  

X 

Natica  (Gyrodes)  lineata,  n.  sp  

X 

X 

.... 

Neptunea  mucronata  Gabb  

X 

X 

.... 

Perissolax  tricarnatus  Weaver  

X 



Einginella  pinguis  Gabb  

X 

.... 

Surcula  merriami,  n.  sp  

X 

.... 

Tritonium  martinezensis,  n.  sp  

X 

X 

X 

Turritella  infragranulata  Gabb  

X 

X 

X 

Turritella  pachecoensis  Stanton  

X 



.... 

Urosyca  caudata  Gabb  

X 

X 

Xenophora  zitteli  Weaver  

X 

Fish  tooth  

X 



Leaf    . 

X 

Of  the  forms  in  the  above  list  the  following  as  far  as  known  are 
characteristic  of  this  lower  zone :  Cidaris,  sp.,  Terebratulina  tejonensis 
Stanton,  Cardita  veneriformis  Gabb,  Gorbula,  sp.,  Leda  milleri,  n.  sp., 
Meretrix  stantoni,  n.  sp.,  Meretrix  dalli,  n.  sp.,  Spisula(f)  weaver i 
Packard,  Zirphaea(f),  sp.  and  Tritonium  martinezemis,  n.  sp.  Schiz- 
aster  lecontei  Merriam  is  very  rare  in  these  beds,  only  one  specimen 
being  found.  The  striking  thing,  however,  is  the  absence  of  such 
forms  as  Trochocyathus  zitteli  (Merriam),  Modiolus  merriami  Weaver, 
Crassatellites  grandis  Gabb,  Anchura  gabbi,  n.  sp.,  Ficopsis,  sp., 
Neptunea  cretacea  Gabb,  and  Surcula  fairbanksi,  n.  sp. 

The  large  number  of  pelecypods  in  comparison  to  the  gastropods 
is  very  noteworthy.  The  coarse  character  of  the  sediments  indicates 
that  they  were  deposited  in  shallow  water  and  in  part  even  within  the 
littoral  zone,  as  the  presence  of  Zirphaea(f),  sp.,  proves.  How  much 
this  depth  factor  was  influential  in  giving  distinctiveness  to  this  fauna 
will  be  discussed  after  the  middle  or  Trochocyathus  zitteli  zone  has 
been  considered. 

FAUNA  OF  THE  TROCHOCYATHUS  ZITTELI  ZONE 
Three  to  four  hundred  feet  above  the  base  of  the  Martinez,  another 
very  distinct  zone  is  found  in  hard,  gray-green,  glauconitic  sandstone. 
This  zone  is  characterized  by  Trochocyathus  zitteli  (Merriam).     Its 
fauna  is  tabulated  below. 


1914]       Dickerson :  Fauna  of  the  Martinez  Eocene  of  California          75 
FAUNA  OF  THE  TROCHOCYATHUS  ZITTELI  ZONE  NORTH  OF  MOUNT  DIABLO 


Loc.     Loc.     Loc.     Loc.     Loc.     Loc.     Loc.     ij^'    -TVVo 

] 

L540    1580    1746    1747    1656    1695    159^ 

Flabellum  remondianum  Gabb  

X           X         —         —         —                          — 

Trochocyathus  zitteli  Merriam  

x        x        x        x        x        x      

v/                    N/                     V                    V                     X                    X 

Cardium  cooperi  Gabb  

xxxxxxxx 

X 

Crassatellites  claytonensis,  n.  sp  

Crassatellites  grandis  (Gabb)   

xxx      x      ....        x 

Crassatellites  unioides  (Stanton)   

x        x        x        x        x      x        x 

Crassatellites  stewartvillensis,  n.  sp.  .. 

Crassatellites  studleyi,  n.  sp  

Cucullaea  mathewsonii  Gabb  

x        x      ....        xxx 

Glycimeris  veatchii  var.  major  (Stan- 

v                               V 

ton)     

x        x      x 

x 

Leda  gabbi  Conrad  

Leda  alaeformis  (Gabb)   

X 

Leda  packardi,  n.  sp  

X 

Lima(?)   claytonensis,  n.  sp  

Lima  haseltinei,  n.  sp  

Macrocallista(f)  packi,  n.  sp  

Meretrix,   sp  

Meretrix  cf  .  stantoni,  n.  sp  

X 

Modiolus,  sp  

Pholadomya  nasuta  Gabb  

x      x      

X 

Paphia  cf  .  clarki,  n.  sp  

Tapes(?)  quadrata  Gabb  

x      x 

Paphia(f),  sp  

x 

Tellina,  sp.,  &  



Tellina  undulifera  Gabb  

x      x      

Teredo,  sp  

Dentalium  cooperi  Gabb  

X           X         ---           X           x           A 

Dentalium,  sp  

Amauropsis  martinezensis,  n.  sp  

x        x      x        x      

Anchura  gabbi,  n.  sp  

Brachysphingus  liratus  Gabb  

xxx      x      x 

Cylichna  costata  Gabb  

x        x 

Discohelix,  sp  

Ficopsis,  sp  

Fusus  mathewsonii  Gabb  

Fusus,  sp  

Heteroterma  striata  Stanton  

x      

Heteroterma  gabbi  Stanton  

Lunatia  hornii  Gabb  

xxx      x      x 

Natica  (Gyrodes)  lineata,  n.  sp  

x      

N/                                                                     X 

Neptunea  mucronata  Gabb  

x        x      x      x 

Neptunea  (Tritonofusus)  cretacea 

Gabb    

x       *• 

Perissolax  tricarnatus  Weaver  
Kinginella  pinguis  Gabb  

x                                         x 

V 

Surcula  merriami,  n.  sp  

Surcula  f  airbanksi,  n.  sp  

76  University  of  California  Publications  in  Geology          [VOL.  8 

FAUNA  OF  THE  TROCHOCYATHUS  ZITTELI  ZONE  NORTH  OP  MOUNT  DIABLO — (Continued} 

Loc.  Loc.  Loc.  Loc.  Loc.  Loc.  Loc.  Loc.  Loc. 
1540  1580  1746  1747  1656  1695  1586  1592  1558 

Surcula,  sp x       

Siphonalia(?)  lineata  Stanton  x       

Turritella  pachecoensis  Stanton  x         x         x       

Turritella  clarki,  n.  sp.  . x       

Tritonium,  sp.,  a  x 

Turris,  sp x       x       

Turris  louderbacki,  n.  sp x       

Urosyca  caudata  Gabb  x        x        x       x       

Xenophora  zitteli  Weaver  x       ....         x         x       


Trochocyathus  zitteli  (Merriam),  Lima  haseltinei,  n.  sp.,  Crassatel- 
lites  stewart villensis,  n.  sp.,  Anchura  gabbi,  n.  sp.,  Ficopsis,  sp.,  Nep- 
tunea  cretacea  Gabb,  Surcula  fairbanksi,  n.  sp.,  and  Turritella  clarki, 
n.  sp.,  are  some  of  the  forms  which  have  not  been  found  in  the 
Meretrix  dalli  zone  or  in  the  Solen  stantoni  zone  at  the  type  locality. 
The  principal  difference  between  this  fauna  and  that  of  the  lower  beds 
is  in  the  ratio  of  the  gastropods  to  the  pelecypods,  viz.,  3:2  in  the 
Trochocyathus  zitteli  zone,  3:4  in  the  Meretrix  dalli  beds.  This 
difference  is  still  greater  when  all  the  gastropods  and  pelecypods  are 
enumerated.  At  least  two  factors  figure  in  the  cause  of  these  differ- 
ences— bathymetric  conditions  and  difference  in  age  of  the  two  zones. 
The  bathymetric  conditions  of  the  lower  beds  have  already  been 
described.  The  genus  Trochocyathus,  according  to  the  "Challenger" 
Report19  ranges  from  a  depth  of  100  to  750  fathoms.  Glauconite  is 
abundantly  formed  at  a  depth  of  a  hundred  fathoms  or  more  in  the 
ocean  of  the  present.  A  study  of  the  gastropods  brings  us  to  the 
same  conclusion,  viz.,  that  the  Trochocyathus  zitteli  beds  were 
deposited  in  at  least  one  hundred  fathoms  of  water.  The  age  differ- 
ence between  the  faunas  of  the  two  zones  is  obvious,  the  one  being 
stratigraphically  above  the  other.  Just  how  much  control  these  two 
factors  exert  is  an  exceedingly  difficult  matter  to  determine.  The 
absence  of  Trochocyathus  in  the  lower  beds  may  be  explained  upon 
a  basis  of  depth  relations,  but  why  certain  forms  such  as  Cardita 
veneriformis  Gabb,  Leda  milleri,  n.  sp.,  Meretrix  dalli,  n.  sp.  Tritonium 
martinezensis,  n.  sp.,  and  Cidaris,  sp.,  a,  should  not  appear  in  the 
Trochocyathus  zitteli  zone  cannot  be  explained  upon  the  same  basis, 
for  apparently  some  of  these  forms  disappeared  before  the  upper 

i»  Moseley,  Challenger  Report,  Zoology,  vol.  2,  part  7,  pp.  132-133,  1881 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          77 

beds  were  deposited.  At  Benicia  an  entire  section  of  Martinez 
appears  to  be  present,  and  in  the  middle  of  the  section  forms  else- 
where associated  with  Trochocyathus  zitteli  are  found  injbejds  which 
were  not  deposited  in  deep  water,  as  is  shown  by  the  absence  of 
Trochocyatkus  zitteli  and  Schizaster  lecontei.  As  none  of  the  above- 
mentioned  forms  occur  here,  difference  in  age  appears  to  be  the 
principal  cause  of  the  faunal  differences. 

MARTINEZ  AND  TEJON  SOUTH  OF  MOUNT  DIABLO 

During  the  field  work  of  the  last  two  University  summer  classes  in 
palaeontology  we  did  not  succeed  in  recognizing  the  Martinez  group 
south  of  Mount  Diablo  until  the  collections  were  correctly  determined. 
The  base  of  the  Tejon  was  found  to  be  in  unconformable  contact  with 
the  underlying  beds  in  three  different  places  six  or  more  miles  apart. 
In  one  locality  (University  of  California  Locality  1308),  the  Tejon 
rests  unconformably  on  a  gray  limestone  of  Martinez  age,  in  another 
locality  upon  a  dark  gray  sandstone  of  Chico  age. 

In  a  locality  on  Little  Pine  Creek  an  angular  unconformity  was 
observed  between  the  overlying  Tejon,  strike  N  20°  W,  dip  7°  S,  and 
the  underlying  Chico  strata,  strike  N  20°  W,  dip  7°  N.  On  the  divide 
between  Pine  and  Curry  canons  an  angular  unconformity  between  the 
Chico  and  the  Tejon  was  recognized,  and  mollusc  borings  were  noted. 
This  unconformable  contact  was  traced  for  over  four  miles  east  of  this 
divide. 

The  underlying  Chico  yielded  only  fragments  of  Inoceramus,  but 
the  basal  beds  of  the  Tejon  are  very  fossiliferous  in  many  places.  At 
a  locality  on  the  ridge  between  Little  Pine  Creek  and  Pine  Canon 
(SE  14  of  NE  %  Sec.  4,  T.  1  S,  R.  1  W,  M.  D.  B.  &  M.)  both  the 
Tejon  and  underlying  limestone  are  fossiliferous.  The  following 
partial  list  shows  the  fauna  which  was  found  in  the  beds  of  the  Tejon 
a  hundred  and  fifty  to  two  hundred  feet  above  the  base. 

Solen  parallelus  Gabb  Pecten,  sp. 

Venericardia  planicosta  Lamarck  Psammobia  hornii  (Gabb) 

Meretrix  hornii  Gabb  Fusus  mathewsonii  Gabb 

Glycimeris,  sp.  Spiroglyphus(f),  sp. 

Leda  gabbi  Conrad  Cylichna  costata  Gabb 

Cardium  breweri  Gabb  Eimella  canalifera  Gabb 

Tapes  conradiana  Gabb  Amauropsis  alveata  Gabb 

Tellina(?),  sp.  Fusus  (?),  sp. 

Acila,  sp.  Surcula,  sp. 


78  University  of  California  Publications  in  Geology          [VOL.  8 

The  unconformity  was  further  marked  by  unmistakable  mollusc 
borings  at  this  point.  The  limestone  contains  a  few  species  of  un- 
doubted Eocene  age.  The  following  forms  have  been  recognized: 

Dosinia  lawsoni,  n.  sp.  Teredo,  sp. 

Phacoides  diaboli,  n.  sp.  Fusus  mathewsonii  Gabb 

Papilla  (?)  clarki,  n.  sp.  Surcula  claytonensis  (Gabb) 

Venus  (?)  martinezensis,  n.  sp.  Aturia  mathewsonii  Gabb 

Of  these  forms  Aturia  mathewsonii  has  been  reported  from  both 
the  Tejon  and  the  Martinez.  The  genus  Aturia  is  wholly  restricted 
to  the  Eocene,  Oligocene,  and  Miocene.  Fusus  mathewsonii  was 
originally  described  from  the  Tejon.  It  also  occurs  in  the  basal  beds  of 
the  Martinez  north  of  Mount  Diablo.  Paphia(f)  clarki,  n.  sp.,  occurs 
in  the  Martinez  north  of  Mount  Diablo.  Surcula  claytonensis  was 
first  described  from  the  upper  portion  of  the  Tejon,  north  of  Mount 
Diablo  in  strata  above  the  Clark,  or  upper  vein  of  coal.  Phacoides 
diaboli,  n.  sp.,  found  here  appears  to  be  the  same  species  as  the 
Phacoides,  n.  sp.,  found  in  the  Eocene  beds  of  San  Pedro  Point.  The 
stratigraphic  evidence,  together  with  a  fauna  of  undoubted  Eocene 
age,  indicate  that  these  underlying  beds  are  Martinez.  The  relation- 
ship of  these  Martinez  beds  to  the  Chico  has  not  been  worked  out. 
One  locality  south  of  Mount  Diablo  where  Chico  fossils  were  found 
is  Curry  Canon.  Mr.  Reginald  Stoner  determined  the  following  from 
this  locality: 

Trigonia  evansana  Baculites,  sp. 

Cucullaea  truncata  Cinulia  obliqua 

Cardium  annulatum  Anchura  calif  ornica 

Venus  varians  Glycimeris  veatchii 

Dentalium  stramineum  Ammonites,  n.  sp. 

Cyprinella  tenuis  Schloenbachia  chicoensis 
Dentalium  cooperi 

At  the  locality  on  the  ridge  between  Pine  Canon  and  Little  Pine 
Canon,  the  thickness  of  Martinez  exposed  cannot  be  more  than  two 
hundred  to  three  hundred  feet,  as  the  Franciscan  schists  and  associated 
serpentine  are  found  only  one-eighth  of  a  mile  away,  and  Cretaceous 
strata  probably  occur  between  the  two. 

It  is  seen  from  this  description  that  the  Martinez  exhibits  some 
lithologic  differences  on  the  north  and  south  sides  of  the  mountain. 
On  the  north  side  of  the  mountain,  the  beds — about  seven  hundred 
feet  thick — in  descending  order  consist  of : 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          79 

(5)   Gray-green  shales,  250-300  feet. 

(4)   Gray-green  glauconitic  sandstone,  50  feet. 

(3)  Fine-grained,  hard,  gray  sandstone,  200  feet. 

(2)   Shales  and  argillaceous  sandstones,  100  feet. 

(1)  A  brown,  conglomeritic,  basal  sandstone,  50  to  100  feet  in  thickness. 


On  the  south  side  of  the  mountain  the  limestone,  ten  feet  in  thick- 
ness, is  interbedded  with  shales  and  fine  gray  micaceous  sandstone. 
From  this  evidence  we  conclude  that: 

1.  An  unconformity  exists  between  the  Tejon  and  beds  evidently 
of  Martinez  age  southwest  of  Mount  Diablo,  as  well  as  between  the 
Tejon  and  Chico. 

2.  This  unconformity  is  marked  by  mollusc  borings  recognized  in 
localities  six  miles  apart,  and  an  angular  unconformity  is  recognizable 
in  several  places  between  the  Tejon  and  the  underlying  Chico. 

Field  relations  show  that  the  unconformity  between  the  Tejon  and 
Martinez  represents  a  time  interval  so  long  that  at  least  several 
hundred  feet  of  thickness  of  Martinez  were  removed  before  the  land 
was  lowered  to  receive  the  sediments  of  the  Tejon  sea  directly  upon 
the  Chico,  the  former  basement  of  the  Martinez. 


TYPE  LOCALITY  OF  THE  MARTINEZ 

STEATIGEAPHY 

Dr.  Weaver20  described  the  stratigraphy  at  the  type  locality  as 
follows : 

In  the  vicinity  of  the  Strait  of  Carquinez  the  Chico,  Martinez,  Tejon  and 
Monterey  have  all  participated  in  the  folding  of  the  strata,  which  has  resulted 
in  the  formation  of  a  synclinal  trough,  the  axis  of  which  has  a  northwest  to 
southeast  trend.  The  apex  is  situated  about  four  miles  to  the  north  of  Benicia. 
The  maximum  width  of  this  syncline,  extending  from  a  short  distance  west  of 
Pacheco  on  the  east  to  Del  Hambre  Canon  on  the  west,  is  about  four  miles. 
In  this  cross-section  the  Chieo,  Martinez,  Tejon  and  Monterey  are  found  in 
succession  toward  the  center  of  the  syncline.  The  same  holds  true  on  the 
northern  side  of  the  straits,  except  that  the  Monterey  is  not  represented.  To 
the  south  and  west  of  Martinez,  on  the  western  limb  of  the  syncline,  all  of 
these  beds  dip  at  high  angles  to  the  northeast.  West  of  the  syncline  the  Martinez 
becomes  thinner,  and  is  represented  by  a  narrow  strip  extending  up  nearly  to 
the  head  of  Del  Hambre  Canon.  At  this  locality  the  Martinez,  together  with 
the  Chico,  dips  to  the  southwest. 


20  Weaver,  C.  E.,  Contribution  to  the  Palaeontology  of  the  Martinez  Group, 
Univ.  Calif.  Publ.  Bull.  Dept.  Geol.,  vol.  4,  no.  5,  p.  105,  1905. 


80  University  of  California  Publications  in  Geology          [VOL.  8 

On  the  eastern  flank  of  the  syncline,  beds  of  Martinez  age  are  represented 
immediately  west  of  Bull's  Head  Point,  and  south  of  this  point  they  appear 
east  of  the  road  leading  from  Pacheco  to  Martinez.  These,  together  with  the 
Chico  and  Tejon,  dip  steeply  to  the  southwest.  The  strike  of  these  beds  carries 
them  across  the  Strait  of  Carquinez,  where  they  again  outcrop  just  north  of 
Army  Point  Station.  At  this  point  the  formation  was  so  thickly  bedded  that 
it  was  difficult  to  obtain  accurate  observations  of  the  dip.  Apparently,  however, 
they  dip  at  high  angles  to  the  southwest.  In  this  locality  the  outcrops  are 
separated  from  both  Chico  and  Tejon  by  low  marshes,  so  that  no  actual  contact 
could  be  observed.  However,  no  marked  irregularity  in  the  dip  was  seen.  The 
strike  of  these  beds  was  traced  to  a  point  about  three  miles  northwest  of 
Benicia.  Farther  than  this  no  outcrops  were  seen  which  could  definitely  be 
called  Martinez.  To  the  west  of  Benicia  thick-bedded  sandstones  closely 
resembling  those  at  Army  Point  were  observed  dipping  steeply  to  the  north- 
east. Farther  west  the  Chico  again  occurs,  dipping  at  the  same  angle  as  the 
thick-bedded  sandstones,  but  near  the  shore  it  is  folded  and  again  dips  to  the 
southwest.  The  strike  and  dip  of  these  beds  where  carried  across  the  straits 
are  almost  identical  with  those  south  and  west  of  Martinez.  The  most  reasonable 
conclusion  would  seem  to  be  that  there  exists  here  a  closely  folded  syncline. 


The  structure  of  the  Martinez  to  the  south  and  west  of  the  town 
of  Martinez  is  not  as  simple  as  Weaver's  description  implies.  Basal 
beds  of  the  Martinez  with  their  associated  fauna  such  as  have  been 
described  above  in  the  Martinez  area  north  of  Mount  Diablo  have  not 
been  recognized  with  certainty,  but  the  Trochocyathus  zitteli  zone  is 
very  thick  in  the  southeastern  portion  of  the  Martinez  between  Canada 
del  Hambre  and  Ignacio  Valley,  a  distance  of  three  miles.  On  the 
southwest  of  this  area,  the  Martinez  is  in  contact  with  the  Monterey. 
Just  what  relation  exists  between  the  two  is  very  difficult  to  discover. 
No  Tejon  appears  to  be  present  along  this  line,  but  near  the  town  of 
Walnut  Creek  the  continuation  of  the  Monterey  strata  is  in  contact 
with  the  Tejon,  so  we  are  inclined  to  think  that  the  Monterey  has 
overlapped  the  Tejon  and  a  part  of  the  Martinez,  and  lies  upon  both 
unconformably.  Outcrops  are  infrequent  along  the  contact  and  are 
in  general  too  poor  to  give  any  decisive  evidence.  The  dips  of  the 
Martinez  in  this  area  are  all  to  the  northeast.  The  area,  however,  is 
twice  as  wide  as  the  distance  between  the  Chico  and  Tejon  at  Muir 
Station.  The  northward  extension  of  this  area  consists  of  two  strips 
of  Martinez  with  a  tongue  of  Chico  between.  The  southern  strip  runs 
northward  for  three  miles  to  Alhambra  Springs.  Here  it  is  cut  off 
by  a  thrust  fault,  which  runs  northward  to  Carquinez  Strait,  where 
Martinez  again  occurs  at  the  Selby  Smelter. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          81 

RELATIONS  TO  THE  MAETINEZ  AT  SELBY  SMELTER 
The  Martinez  at  Selby  Smelter  is  traceable  southward  to  the 
southern  edge  of  the  Napa  Quadrangle  sheet  near  ChristieT Station  on 
the  Santa  Fe  railroad,  a  distance  of  six  miles.  Extensive  overthrust- 
ing  has  occurred,  so  that  in  places  the  Chico  has  completely  over- 
ridden the  Martinez  and  even  a  part  of  the  Monterey.  The  Martinez 
at  Selby  was  probably  once  connected  with  the  southernmost  tongue 
of  Martinez  of  the  type  locality,  as  their  extensions  are  separated  by 
a  distance  of  only  two  miles.  A  conglomerate  in  the  Martinez  is 
found  one  quarter  of  a  mile  north  of  Vaca  Canon  near  the  Chico. 
A  small  conglomerate  area  also  occurs  about  one-half  to  three-quarters 
of  a  mile  north  of  Vaca  Canon.  Both  dip  at  high  angles  to  the  north. 
Whether  these  conglomerates  are  basal  it  is  impossible  to  determine 
positively  from  poor  exposures  and  lack  of  fossils,  but  that  such  is 
the  case  is  strongly  suggested.  The  great  area  of  Martinez  southeast 
of  Canada  del  Hambre,  the  tongue  of  Chico  coming  in  between  the 
two  extensions  of  the  Martinez  and  a  probable  basal  conglomerate 
indicate  that  we  have  a  closely  folded,  overturned  anticline  in  this 
portion  of  the  type  section  which  is  locally  broken  by  both  strike  and 
cross-faults.  On  account  of  these  structural  complications,  very  small 
exposures,  if  any,  of  the  true  base  of  the  Martinez  occur  at  the  type 
section;  but  the  major  exposures  are  those  of  the  upper  and  middle 
portions  of  the  group.  Although  the  localities  at  Selby  and  Benicia 
are  structurally  connected  with  the  type  locality,  it  is  best  to  consider 
them  separately. 

FAUNAL  ZONES 

We  are  chiefly  indebted  to  Merriam  and  Weaver  for  the  recognition 
of  two  distinct  faunal  zones  at  the  type  section,  viz.,  the  Trochocyathus 
zitteli  and  the  Solen  stantoni  zones.  Many  students  in  the  field  classes 
in  palaeontology  have  collected  near  Muir  Station,  and  from  all  of 
these  sources  the  writer  has  determined  the  faunas  listed  below.  What 
the  persistent  efforts  of  collectors  will  accomplish  is  well  illustrated 
by  these  lists  when  one  knows  how  poor  the  collecting  really  is  in 
this  field. 


82                University  of  California  Publications  in  Geology  LV°L- 8 
TEOCHOCYATHUS  ZITTELI  ZONE  OF  THE  TYPE  LOCALITY 

Loc.  Loc.    Loc.   Loc.   Loc.   Loc. 

500-243  333     65     544    267    1547 

Flabellum  remondianum  Gabb  x  ....           x           x 

Trochocyathus  zitteli  (Merriam)  x  x                       x 

Schizaster  lecontei  Merriam  x  

Serpula,  sp x         

Avicula(?),  sp x 

Anatina,   sp x 

Cucullaea  mathewsonii  Gabb x  ....           x         ....           x           x 

Cuspidaria  hannibali,  n.  sp ....         ....         ....         ....           x 

Cardium  cooperi  Gabb  x  ....          x         x 

Crassatellites  studleyi,   n.sp x  

Crassatellites  claytonensis,  n.  sp.  .; ....         ....         ....         ....           x 

Dosinia  lawsoni,  n.  sp x 

Leda  gabbi  Conrad  x  

Lima  multiradiata  Gabb  x 

Lima  haseltinei,  n.  sp x 

Modiolus  bakeri,  n.  sp X  

Modiolus  merriami  (Weaver)  x  x         

Modiolus  ornatus   (Gabb)   x 

Nucula  (Acila)  cf.  truncata  Gabb  x  x         x 

Pinna  barrowsi,  n.  sp x  x 

Phacoides  turneri  (Stanton)  ....           x 

Phacoides  muirensis,  n.  sp x 

Pholadomya  nasuta  Gabb  x  x          x         x 

Psammobia  hornii  (Gabb) x  

Solen,  sp x 

Tapes  (?)  quadrata  Gabb  x  

Tellina  undulifera  Gabb x  

Teredo,  sp x         

Dentalium  cooperi  Gabb  x  ....         ....         ....         ....           x 

Actaeon  lawsoni  Weaver  x  

Anchura  englishi,  n.  sp x  

Amauropsis  martinezensis,  n.  sp x  ....           x 

Architectonica,  sp x 

Cylichna  costata  Gabb  x  x 

Discohelix  calif ornicus  Weaver  x  ....         ....         ....         ....           x 

Fusus  aequilateralis  Weaver  x  

Fusus  (?),  sp.,  a x  x         

Fusus  flexuosus  Gabb  x 

Fusus  mathewsonii  Gabb  x  ....           x         

Fusus  martinez  Gabb  x  ....           x 

Fusus(?),  sp.,  b  x  

Fusus  occidentalis  Gabb  x  

Fusus  cf.  aratus  Gabb  : x 

Ficopsis,   sp x         

Lunatia  hornii  Gabb  x 

Neptunea  mucronata  Gabb  x 

Natica  (Gyrodes)  lineata,  n.  sp X  

Nerita(?)  biangulata,  n.  sp x         


1914]      Dicker  son:  Fauna  of  the  Martinez  Eocene  of  California          83 


TROCHOCYATHUS  ZITTELI  ZONE  OF  THE  TYPE  LOCALITY — (Continued) 


Loc.      Loc. 
500-243     333 


Loc. 
65 


Loc. 
544 


Loc. 
267 


Loc. 
1547 


Naticina,  sp 

Perissolax  tricarnatus  Weaver  

Einginella  pinguis  Gabb  

Siplionalia(?)  lineata  Stanton  

Surcula  (Surculites)  andersoni,  n.  sp 

Surcula  merriami,  n.  sp 

Turbinella  erassatesta  Gabb  

Turris  louderbacki,  n.  sp 

Urosyca  caudata   Gabb   

Urosyca  robusta  Weaver  

Hercoglossa  merriami,  n.  sp 

Nautilus  stephensoni,  n.  sp  

Shark  tooth  .. 


A  comparison  of  this  list  with  that  of  the  Trockocyathus  zitteli 
zone  north  of  Mount  Diablo,  as  might  be  expected,  will  bring  out  some 
differences.  The  following  are  common  to  the  two  localities : 


Flabellum  remondianum  Gabb 
Trochocyathus  zitteli  (Merriam) 
Cardium  eooperi  Gabb 
Cucullaea  mathewsonii  Gabb 
Crassatellites  stewartvillensis,  n.  sp. 
Tapes  (?)   quadrata  Gabb 
Tellina  undulifera  Gabb 
Teredo,  sp. 

Amauropsis  martinezensis,  n.  sp. 
Cylichna  costata  Gabb 


Ficopsis,  sp. 

Fusus  matthewsonii  Gabb 
Neptunea  mucronata  Gabb 
Perissolax  tricarnatus  Weaver 
Siphonalia(?)  lineata  Swanton 
Surcula  merriami,  n.  sp. 
Turritella  pachecoensis  Stanton 
Urosyca  caudata  Gabb 
Xenophora  zitteli  Weaver 


Practically  all  of  these  species  are  common  forms  and,  if  they 
occur  at  all,  they  are  abundant.  The  lists  appear  quite  different  on 
their  face,  but  this  difference  is  due  almost  wholly  to  the  occurrence 
of  species  of  which  but  single  specimens  have  been  found.  Thus, 
among  the  Fusidae  listed  from  the  type  locality  only  two,  Fusus(f), 
sp.,  a,  and  Fusus  martinez  Gabb,  are  reported  from  more  than  one 
locality,  and  of  the  rest  only  individual  specimens  have  been  found 
thus  far.  In  many  of  the  other  cases  the  same  thing  is  true. 
Brachysphingus  liratus  Gabb  is  not  reported  from  the  type  locality, 
but  it  occurs  at  Selby,  which  is  the  same  horizon  without  doubt.  A 
few  widespread  abundant  forms  are  of  more  real  value  than  forms 
which  occur  occasionally.  Thus,  Trochocyathus  zitteli  (Merriam), 
Amauropsis  martinezensis,  n.  sp.,  Crassatellites  stewartvillensis,  n.  sp., 


84 


University  of  California  Publications  in  Geology          [VOL.  8 


Neptunea  mucronata  Gabb,  Xenophora  zitteli  Weaver,  do  not  range 
into  uppermost  Martinez  and  most  of  these  forms  occur  frequently 
enough  to  be  useful  within  certain  limits  to  determine  horizons. 
Since  most  of  these  occur  in  the  basal  beds  north  of  Martinez  such 
forms  will  serve  to  distinguish  between  the  uppermost  Martinez  and 
the  Trochocyathus  zitteli  zone.  Thus  far,  Trochocyathus  zitteli 
(Merriam)  is  the  most  useful  fossil  in  the  recognition  of  the  middle 
zone  of  the  Martinez.  The  middle  zone  of  the  type  section  resembles 
the  middle  zone  of  the  area  north  of  Mount  Diablo  in  the  ratio  of 
gastropods  to  pelecypods,  which  is  approximately  4:3. 

The  absence  of  certain  species  which  occur  in  the  basal  beds  north 
of  Mount  Diablo  is  another  noteworthy  point.  Practically  the  list 
cited  above  in  the  comparison  of  the  basal  and  middle  zones  north 
of  Mount  Diablo  holds  here  as  well.  Such  is  the  evidence  for  correlat- 
ing the  two  Trochocyathus  zitteli  beds  in  these  two  areas.  In  the 
opinion  of  the  writer  they  appear  to  be  of  approximately  the  same  age. 

The  uppermost  or  Solen  stantoni  zone  was  first  described  by 
Weaver,  although  Merriam  previously  suggested  a  faunal  difference 
between  the  upper  and  lower  beds.  Weaver  lists  the  following  from 
this  zone : 


UPPER  MARTINEZ 


Foraminifera  nummuloid 
Schizaster  lecontei  Merriam 
Cancer,  sp. 
Area  biloba  Weaver 
Cardita  hornii  Gabb 
Cardium  cooperi  Gabb 
Cucullaea  mathewsonii  Gabb 
Leda  gabbi  Conrad 
Modiolus  merriami  (Weaver) 
Modiolus  ornatus  (Gabb) 
Dentalium  cooperi  Gabb 
Dentalium  stramineum  Gabb 
Ficopsis  angulatus  Weaver 
Heteroterma  gabbi  Stanton 
Heteroterma  trochoidea  Gabb 
Heteroterma,  indet. 
Megistostoma  striata  Gabb 
Cassidaria  tuberculata  (Gabb) 
Natica,  sp. 
Perissolax  tricarnatus  Weaver 


Perissolax  blakei  Gabb 
Solen  stantoni  Weaver 
Tellina  martinezensis  Weaver 
Tellina  hornii  Gabb 
Tellina  undulifera  Gabb 
Thracia  karquinezensis  Weaver 
Ampullina  (conf.)  striata  Gabb 
Brachysphingus  liratus  Gabb 
Bullinula  subglobosa  Weaver 
Siphonalia(f),  lineata  Stanton 
Architectonica  tuberculata  Weaver 
Strepsidura  pachecoensis  Stanton 
Tritonium  impressum  Weaver 
Tritonium  pulchrum  Weaver 
Tritonium  eocenicum  Weaver 
Turritella  infragranulata  Gabb 
Turritella  pachecoensis  Stanton 
Turritella  conica  Weaver 
Turris,  sp.  indet. 
Urosyca  caudata  Gabb 


Of  these  forms  Tellina  martinezensis,  Bullinula  subglobosa,  Hetero- 
terma trochoidea,  Megistostoma  striata(f),  Architectonica  tuberculata, 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          85 

Strepsidura  pachecoensis,  Tritonium  pulchrum,  and  Turritella  conica 
have  not  as  yet  been  found  in  a  lower  horizon.  Ficopsis  angulatus, 
Cassidaria  tuberculatus,  Tritonium  impressum,  Tritonium_eocenicum, 
also  reported  as  not  present  in  the  lower  beds,  were  really  found  in 
beds  just  above  the  Martinez,  that  is,  in  the  basal  Tejon.  All  of  these 
forms  come  from  University  of  California  Locality  337,  where  they 
are  associated  with : 

NummuloidC?),  sp.  Bela  cf.  clathrata  Gabb 

Orbitoides,  sp.  Ficopsis  remondii  Gabb 

Schizaster  lecontei  Merriam  Megistostoma  striata  Gabb 

Cardium  cooperi  Gabb  Cassidaria  tuberculata  (Gabb) 

Modiolus  merriami  (Weaver)  Eimella  canalifera  Gabb 

Psammobia  hornii  (Gabb)  Spiroglyphus  (  ?)  tejonensis  Arnold 

Tellina  martinezensis  Weaver  Turris  monolifera  Cooper 

Solen  parallelus  Gabb  Tritonium  eocenicum  Weaver 
Venericardia  planicosta  Lamarck 

Of  these  forms  Eimella  canalifera,  Venericardia  planicosta,  var. 
hornii,  Bela  clathrata,  Megistostoma  striata,  Cassidaria  tuberculata, 
Turris  monolifera  and  Spiroglyphus(f)  tejonensis  are,  as  far  as  the 
writer  knows,  typical  Tejon  forms  and  they  all  occur  in  the  basal  beds 
of  the  Tejon  south  of  Mount  Diablo.  The  others,  except  the  unplaced 
species  described  by  Weaver,  are  all  found  in  the  Tejon.  Ficopsis 
angulatus  Weaver  is  not  a  valid  species  but  a  variety  of  F.  remondii 
Gabb,  and  along  with  this  we  must  regard  the  others  as  Tejon  forms 
from  its  lower  portion. 

Thracia  karquinezensis  Weaver  was  found  at  University  of  Cali- 
fornia Locality  532,  which  is  on  the  same  horizon  as  537.  Its  associates 
were  Perissolax,  n.  sp.,  and  Solen  stantoni  Weaver.  Although  Solen 
stantoni  Weaver  is  not  wholly  restricted  to  the  uppermost  Martinez, 
it  is  a  characteristic  and  abundant  form  of  this  horizon.  One  specimen 
has  been  found  in  the  basal  beds  of  the  Martinez  and  it  also  occurs  in 
the  Tejon  near  the  base  in  the  Muir  syncline. 

Below  is  given  a  revised  list  of  the  fauna  of  the  upper  Martinez, 
or  the  Solen  stantoni  beds. 

EEVISED  LIST  OF  SPECIES  OF  SOLEN  STANTONI  ZONE 

Loc.         Loc.          Loc.    Listed  by 
213-501      541          1828      Weaver 

Flabellum  remondianum  Gabb  ....  ....  x 

Schizaster  lecontei  Merriam  ....  ....  x 

Cucullaea  mathewsonii  Gabb  x 

Cardium  cooperi  Gabb x 

Leda  gabbi  Conrad  x 


86 


University  of  California  Publications  in  Geology          [VOL.  8 


REVISED  LIST  OF  SPECIES  OF  SOLEN  STANTONI  ZONE — (Continued} 


Loc.         Loc. 
213-501      541 


Loc. 
1828 


Listed  by 
Weaver 


Meretrix,  sp 

Modiolus  ornatus  (Gabb)  x 

Modiolus  merriami  (Weaver)  ....  ....  X 

Nucula  (Acila)  truncata  Gabb  ....  ....  x 

Pholadomya  nasuta  Gabb  ....  x 

Psammobia(?)  cylindrica,  n.  sp ....  x 

Psammobia  hornii  (Gabb)  x 

Solen  stantoni  Weaver  x  ....  x 

Solen,  sp x 

Tellina  martinezensis  Weaver ....  ....  y 

Tellina  undulifera  Gabb  x 

Tellina  aequalis  Gabb  x 

Teredo,  sp — .  x 

Ampullina  cf.  striata  Gabb  ....  ....  x 

Architectonica  tuberculata  Weaver x 

Brachysphingus  liratus  Gabb  x 

Bullinula  subglobosa  Weaver  x 

Cylichna  costata  Gabb  ....  x 

Dentalium  cooperi  Gabb  x 

Dentalium  stramineum  Gabb  ....  ....  x 

Fusus  occidentalis  Gabb  x 

Fusus  mathewsonii  Gabb  x 

Fusus  aequilateralis  Gabb  x 

Heteroterma  gabbi  Stanton  x 

Heteroterma  trochoidea  Gabb  x 

Heteroterma,  indet ....  ....  x 

Lunatia,  sp x 

Lunatia  hornii  Gabb  ....  x 

Megistostoma(?),  sp.  Gabb  x 

Perissolax  tricarnatus  Weaver  ....  ....  x 

Siphonalia(?)  lineata  Stanton  x  ....  x 

Strepsidura  pachecoensis  Stanton  x  x 

Tritonium  pulchrum  Weaver  x 

Turritella  infragranulata  Gabb  x 

Turritella  pachecoensis  Stanton  

Turritella  conica  Weaver  x 

Turris,  sp.,  indet ....  ....  x 

Urosyca  caudata  Gabb  x 


But  one  specimen  each  of  Architectonica  tuberculata  Weaver, 
Bullinula  subglobosa  Weaver  and  Megistostoma(f),  sp.  Gabb  have  been 
found  in  these  upper  beds.  The  number  of  guide  fossils  is  really  very 
small.  Solen  stantoni  has  not  been  found  in  the  Trochocyathus  zitteli 
zone,  but  it  is  reported  from  the  basal  beds  north  of  Mount  Diablo. 
Strepsidura  pachecoensis  Stanton  and  Turritella  conica  Weaver  appear 
to  be  the  only  others  which  are  restricted  to  this  horizon.  The  absence 


1914]      Dicker  son:  Fauna  of  the  Martinez  Eocene  of  California          87 

of  several  species  which  occur  in  the  middle  or  Trochocyathus  zitteli 
zone  is  the  noteworthy  feature  of  the  Solen  stantoni  beds.  Among 
these  are  Trochocyathus  zitteli  (Merriam),  Crassatellites  unioides 
Stanton,  Glycimeris  veatchii  var.  major  (Stanton),  Leda  alaeformis 
(Gabb),  Meretrix  stantoni,  n.  sp.,  Paphia(f)  clarki,  n.  sp.,  Amauropsis 
martinezensis,  n.  sp.,  Discohelix  calif ornica  Weaver,  Neptunea  cretacea 
Gabb,  and  Xenophora  zitteli  Weaver. 


MARTINEZ  AT  BENICIA 

The  Martinez  at  Benicia  is  a  continuation  of  the  eastern  limb  of 
the  Muir  syncline,  a  portion  of  the  type  section.  The  best  exposures 
are  found  in  the  Arsenal  Grounds.  Basal  beds  of  the  Martinez  are 
exposed  in  a  rock  quarry  about  one  hundred  yards  west  of  the 
Arsenal  Reservoir  Hill.  They  are  composed  of  about  twenty  feet  of 
conglomerate,  upon  which  is  laid  about  fifty  feet  of  fine-grained  white 
foraminiferal  shale  with  strike  N  60°  W,  dip  55°  W.  Unfortunately 
minor  faulting  has  so  complicated  the  structure  that  the  relation  to 
the  underlying  Chico  is  not  clear.  The  basal  beds  are  non-f ossilif  erous, 
but  the  glauconitic  sandstone  beds  one  thousand  feet  above  the  base 
contain  fossils. 

The  following  species  have  been  reported  from  this  locality : 


Flabellum  remondianum  Gabb 
Terebratulina  tejonensis  Stanton 
Cucullaea  mathewsonii  Gabb 
Glycimeris  veatchii  var.  major 

(Stanton) 

Leda  gabbi  Conrad 
Leda  alaeformis  (Gabb) 
Meretrix  cf.  dalli,  n.  sp. 
Meretrix,  sp. 
Meretrix  stantoni,  n.  sp. 
Nucula  truncata  Gabb 
Phacoides  diaboli,  n.  sp. 
Pholadomya  nasuta  Gabb 


Tapes  (?)  quadrata  Gabb 
Tellina(?)  undulifera  Gabb 
Tellina(?),  sp.  a 
Actaeon  lawsoni  Weaver 
Ampullina  (conf.)  striata  Gabb 
Brachysphingus  liratus  Gabb 
Discohelix  californica  Weaver 
Natica,  sp. 

Perissolax  tricarnatus  Weaver 
Turbinella  crassatesta  Gabb 
Turritella  infragranulata  Gabb 
Urosyca  caudata  Gabb 


Cassidaria  tuberculata  was  in  the  old  collections  made  by  Dr. 
Weaver,  but  it  may  have  been  mixed  in  from  a  Tejon  collection.  Its 
sandstone  matrix  appears  different  from  the  Martinez  sandstone. 

All  of  the  other  forms  occur  in  the  Trochocyathus  zitteli  zone  either 
at  the  type  locality  or  in  the  area  north  of  Mount  Diablo.  Meretrix 
stantoni,  n.  sp.,  Meretrix  dalli,  n.  sp.,  Tellina,  n.  sp.,  a,  Discohelix  cali- 
fornica, Turbinella  crassatesta,  Terebratulina  tejonensis,  Glycimeris 


88  University  of  California  Publications  in  Geology          [VOL.  8 

veatchii  var.  major,  Leda  alaeformis,  Actaeon  lawsoni  do  not  occur  in 
the  uppermost  Martinez.  Although  the  fauna  is  small,  it  appears 
sufficient  to  correlate  it  with  the  Trochocyathus  zitteli  zone  of  the  type 
section.  Dr.  Stanton21  reports  the  following  fauna  from  beds  "  several 
hundred  feet  higher  in  the  section": 

Modiolus  ornatus  (Gabb)  Fusus  flexuosus  Gabb 

Glycimeris  sagittata  (Gabb)?  Turritella  infragranulata  Gabb 

Nucula  truncata  Gabb  Brachysphingus  liratus  Gabb 

Meretrix,  sp.  Cylichna  costata  Gabb 

Tellina(?)  undulifera  Gabb  Actaeon,  sp. 
Tellina  hoffmaniana  Gabb 

This  fauna  comes  from  the  upper  beds.  The  Martinez  exposed 
along  the  Carquinez  Strait  probably  includes  the  three  major  zones. 
The  lack  of  fossils  makes  it  a  poor  section  for  the  palaeontologist, 
but  for  the  geologist  is  is  one  of  the  best  in  the  vicinity. 

MARTINEZ  AT  SELBY  SMELTER 

This  locality  was  discovered  by  Robert  Pack  and  Clark  Gester  while 
students  in  the  University  of  California.  J.  R.  Powers  made  thorough 
collections  in  both  the  Chico  and  the  Martinez  near  the  Southern 
Pacific  tunnel.  The  writer  has  identified  most  of  the  material  collected 
at  this  locality  (no.  1888). 

LIST  OF  SPECIES 

Flabellum  remondianum  Gabb  Amauropsis  martinezensis,  n.  sp. 

Trochocyathus  zitteli  (Merriam)  Brachysphingus  liratus  Gabb 

Schizaster  lecontei  Merriam  Dentalium  cooperi  Gabb 

Cucullaea  mathewsonii  Gabb  Fusus (?),  n.  sp. 

Cardium  cooperi  Gabb  Fusus  (?),  sp. 

Glycimeris,  sp.  Heteroterma  gabbi  Stanton 

Leda  gabbi  Conrad  Perissolax  tricarnatus  Weaver 

Nucula  (Acila)  truncata  Gabb  (I)  Surcula  near  praeattenuata  Gabb 

Ostraea  weaveri,  n.  sp.  Surcula  (Surculites)  inconspicua 

Phacoides  turneri  (Stanton)  Gabb 

Solen,  sp.  Surcula  merriami,  n.  sp. 

Tellina  kewi,  n.  sp.  Turritella,  sp. 

Tellina,  sp.  Urosyca  caudata  Gabb 

Serpula,  sp.  Urosyca  robusta  Weaver 

This  fauna  evidently  belongs  to  the  Trochocyathus  zitteli  zone. 
As  in  nearly  all  new  Martinez  localities,  new  or  unplaced  forms 
occur  here,  such  as  Surcula  near  praeattenuata  Gabb,  Surcula 


21  Stanton,  T.  W.,  The  Faunal  Kelations  of  the  Eocene  and  Upper  Cretaceous 
on  the  Pacific  Coast,  17th  Ann.  Kept.  U.  S.  Geol.  Surv.,  p.  1024,  1895-6. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          89 

(Surculites)  inconspicua  Gabb,  Ostrea  weaveri,  n.  sp.,  Tellina  kewi, 
n.  sp.  This  fauna  was  found  in  gray-green  glauconitic  sandstone 
typical  of  the  Trochocyathus  zitteli  zone.  Although  Chico  jossils  have 
been  found  only  a  short  distance  away,  no  basal  Martinez  beds  appear. 
Evidently  they  were  covered  by  the  overthrust  of  the  Chico  upon  them. 
The  Martinez  sandstone  containing  fossils  at  Selby  Smelter  is  one  or 
two  hundred  feet  thick.  Above  this  lie  four  or  five  hundred  feet  of 
gray-green  foraminiferal  shale  with  a  little  interbedded  sandstone. 
This  shale  is  in  turn  overlain  unconformably  by  the  Monterey. 
Whether  this  shale  at  the  contact  is  Tejon  or  Martinez  is  difficult  to 
determine,  as  it  has  thus  far  yielded  only  poorly  preserved  foramini- 
fers.  Good  exposures  are  not  common  in  this  vicinity  and  the  struc- 
ture is  complicated.  One-quarter  of  a  mile  south  of  Selby,  and  about 
two  hundred  feet  from  the  Eocene-Monterey  contact,  the  writer  found 
Urosyca  caudata  and  one  or  two  other  Martinez  species  in  sandstone 
exposed  in  a  road  cut.  This  leaves  but  two  hundred  feet  of  strata 
which  could  be  assigned  to  the  Tejon  at  this  place.  Since  no  Tejon 
has  been  found  along  the  Monterey  contact  for  several  miles  to  the 
south,  it  appears  that  the  shales  underlying  the  Monterey  are  probably 
Martinez. 


MARTINEZ  AT  LOWER  LAKE,  LAKE  COUNTY 

TRANSITIONARY  BEDS  OF  GABB 

Gabb22  referred  to  the  Transitionary  Beds  of  Lower  Lake  as  fur- 
nishing some  of  the  most  important  evidence  indicating  the  continuity 
between  his  "Cretaceous  A"  and  "Cretaceous  B."  That  author 
stated  that  he  found  at  a  "  locality  near  Clear  Lake  .  .  .  within  a  space 
of  two  feet  ....  an  admixture  of  upper  and  lower  forms  proving  the 
existence  of  a  transitionary  bed  or  group  of  beds. ' ' 

Although  geologists  of  the  present  day  do  not  accept  his  view  we 
shall  see  in  the  discussion  which  follows  that  Gabb  appreciated  the 
peculiarities  of  the  fauna  found  here.  His  keen  vision  is  particularly 
worthy  of  note  when  we  remember  that  he  had  no  libraries  or  collec- 
tions containing  comparative  material  to  consult.  A  virgin  field  was 
his,  with  all  the  difficulties  that  usually  confront  the  pioneer  in  science. 


22  Gabb.,  W.  M.,  Proc.  Cal.  Acad.  Nat.  Sci.,  vol.  3,  p.  302,  1866. 


1914]      Dicker  son:  Fauna  of  the  Martinez  Eocene  of  California          91 


ST ANTON'S  DISCUSSION  OF  THE  FAUNA 

Stanton23  visited  the  Lower  Lake  locality  in  1895.     He  described 
it  as  follows : 

Another  important  locality  is  near  the  village  of  Lower  Lake,  in  Lake 
County  about  75  miles  north  of  San  Francisco,  where  Gabb  reported  the 
discovery  of  intermediate  beds  which  showed  a  commingling  of  the  Chico  and 
Tejon  faunas  in  a  single  thin  stratum.  Gabb's  list  of  fossils  from  one  mile 
southeast  of  Lower  Lake  is  as  follows: 


Avicula  pellucida  Gabb 
Lima  multiradiata  Gabb 
Axinaea  veatchi  Gabb 
Cucullaea  mathewsonii  Gabb 
Crassatella  grandis  Gabb 
Tapes  conradiana  Gabb 
Corbula  alaeformis  Gabb 
Turritella  saffordi  Gabb 
Amauropsis  alveata  (Conrad) 


Gyrodes  expansa  Gabb 
Lunatia  shumardiana  Gabb 
Galerus  excentricus  Gabb 
Spirocrypta  pileum  Gabb 
Brachysphingus  liratus  Gabb 
Perissolax  brevirostris  Gabb 
Fusus  californicus  Gabb 
Fasciolaria  laeviuscula  Gabb 


Considerable  collections  were  made  by  me  [Stanton]  from  the  original 
locality  on  Herndon  Creek,  and  also  from  material  taken  from  a  well  at  an 
old  brickyard  one-fourth  mile  nearer  town,  but  on  the  same  horizon.  The 
following  species  were  obtained: 


Flabellum  remondianum  Gabb? 

fragment 

Terebratulina  tejonensis  Stanton 
Plicatula  ostreaformis  Stanton 
Lima  multiradiata  Gabb 
Perna,  sp. 

Modiola  ornata  Gabb 
Cucullaea  mathewsonii  Gabb 
Pectunculus  veatchi,  var.  major 

Stanton 

Leda  gabbi  Conrad 
Leda  alaeformis  Gabb  =  Corbula 

alaeformis 

Crassatella  unioides  Stanton 
Venericardia  planicosta  Lamarck 
Lucina  turneri  Stanton 
Meretrix,  sp. 
Tellina  hornii  Gabb? 
Tellina  aequalis  Gabb 
Tellina  hoffmaniana  Gabb 


Solen  parallelus  Gabb 
Dentalium  cooperi  Gabb 
Patella,  sp. 
Turritella  pachecoensis  Stanton 

T.  saffordi  Gabb 
Turritella  martinezensis  Gabb 
Turritella  infragranulata  Gabb 
Lunatia  hornii  Gabb 
Ampullina  striata  Gabb 
Galerus  excentricus  Gabb 
Cerithiopsis  alternata  Gabb 
Brachysphingus  liratus  Gabb 
Urosyca  caudata  Gabb 
Heteroterma  gabbi  Stanton 
Heteroterma  striata  Stanton 
Siphonalia(?)   lineata  Stanton 
Cypraea  bayerquei  Gabb 
Actaeon,  sp. 
Cylichna  costata  Gabb? 


While  this  list  contains  several  species  that  have  not  been  found  else- 
where, it  also  contains  a  large  proportion  of  the  most  characteristic  forms  of 
the  lower  Tejon  at  Benicia  (Army  Point)  and  near  Pacheco,  so  that  there 

23  Stanton,  T.  W.,  The  Faunal  Relations  of  the  Eocene  and  Upper  Cretaceous 
on  the  Pacific  Coast,  17th  Ann.  Kept.  U.  S.  Geol.  Surv.,  p.  1024,  1895-6. 


92  University  of  California  Publications  in  Geology          [V°L-  & 

can  be  no  doubt  that  practically  the  same  horizon  is  represented  at  all  three 
places.  Chico  species,  with  the  exception  of  forms  that  appear  to  be  specifically 
identical  with  Pectunculus  veatchi  and  Tellina  hoffmaniana,  are  absent.  One  of 
the  forms  which  I  have  referred  to  Heteroterma  was  probably  identified  by 
Gabb  as  Perissolax  brevirostris,  and  his  Gyrodes  expansa  was  probably  also  an 
erroneous  identification. 

The  palaeontological  evidence,  therefore  warrants  the  reference  of  the 
"intermediate  beds"  to  the  lower  part  of  the  Tejon  as  it  is  developed  in  the 
Mount  Diablo  region,  where  some  localities  of  the  same  zone  must  have  been 
included  in  Gabb's  Martinez  Group. 

Owing  to  the  absence  of  other  recognizable  horizons,  the  stratigraphy  of 
the  Lower  Lake  region  adds  little  to  our  knowledge  of  the  position  of  the  zone. 
The  fossils  enumerated  above  occur  not  more  than  300  to  400  feet  north  of 
the  southern  edge  of  a  belt  about  two  miles  wide,  consisting  largely  of  light- 
colored  sandstones  with  some  beds  of  clay  and  bands  of  conglomerate.  The 
strike  is  nearly  east  and  west,  and  the  dip  is  very  high,  often  vertical.  South 
of  this  sandstone  there  are  heavy  beds  of  crumpled  clay  shales  with  thin 
sandstones  and  occasional  calcareous  lenses.  These  are  doubtless  of  Cretaceous 
age,  but  in  the  absence  of  fossils  their  exact  horizon  could  not  be  determined. 
Precisely  similar  beds  occur  on  the  north  side  of  the  sandstone  belt  at  a 
locality  on  the  north  side  of  Cache  Creek  about  two  and  a  half  miles  northwest 
of  Lower  Lake,  and  some  400  feet  within  the  sandstone  belt  a  number  of  the 
Lower  Tejon  species  were  found,  including 

Tellina,  sp. 

Ostrea  appressa  Gabb  Dentalium  cooperi  Gabb 

Perna,  sp.  Turritella  pachecoensis  Stanton 

Leda  alaeformis  (Gabb)  Natica,  sp. 

Meretrix,  sp.  Ancillaria,  sp. 

This  locality  is  about  two  miles  across  the  strike  from  the  localities  that 
yielded  the  larger  collection  from  the  same  horizon.  It  is  evident  that  we 
have  here  a  closely  folded  syncline,  the  rocks  between  the  two  localities  of 
Lower  Tejon  probably  having  a  thickness  of  3000  or  4000  feet.  The  few  fossils 
that  have  been  found  in  the  intervening  beds  include  an  Ostrea,  a  Natica,  and 
Crassatella  uvasana  Conrad,  the  latter  being  an  upper  Tejon  species.  Possibly 
there  are  later  beds  in  the  middle  of  the  fold,  but  it  is  more  probable  that  the 
entire  thickness  belongs  to  the  Tejon. 


STKATIGRAPHY  AND  STRUCTURE 

Dr.  Weaver  later  visited  the  Lower  Lake  section  and  made  a  collec- 
tion of  fossils  from  the  locality  on  Herndon  Creek.  In  August,  1912, 
Packard  and  Dickerson,  while  collecting  fossils  for  the  Department  of 
Palaeontology  of  the  University  of  California,  made  a  stratigraphic 
study  of  the  Eocene  series  and  the  beds  in  contact  with  them.  The 
accompanying  map  (fig.  4)  was  made  at  that  time.  The  Eocene  in 
this  region  is  folded  in  a  plunging  asymmetric  syncline  with  an  east- 
west  axis  which  is  located  nearer  to  the  steeply  dipping  south  limb 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          93 

of  the  fold.  This  syncline  plunges  toward  the  west.  Both  the  Tejon 
and  Martinez  are  found  in  this  fold.  The  Martinez  rests  upon  the 
Chico,  Knoxville,  and  Franciscan  and  on  the  west  it  is  overlapped  by 
the  later  "Cache  Lake"  beds,  andesitic  lava  flows,  and  alluvium. 

The  Franciscan  in  this  region  consists  of  a  typical  complex  of 
diabase,  radiolarian  cherts,  seamed  quartzitic  sandstone,  fine-grained, 
dark  gray  schists,  and  bedded  foraminiferal  limestones.  Serpentine  is 
intruded  as  small  dikes  in  the  sedimentaries.  This  series  appears  to 
be  in  fault  contact  with  the  Chico  on  the  south  side  of  the  syncline 
described  above  and  the  Martinez  appears  to  rest  upon  it  uncon- 
formably. 

A  small  area  of  Knoxville  appears  in  contact  with  Martinez  on  the 
extreme  eastern  limit  of  the  Martinez  area.    It  consists  of  a  dark  gray 
limestone  and  shale  containing  well-preserved  specimens  of  Aucella 
piochii  Gabb.    The  main  Chico  area  borders  the  Martinez  on  the  south. 
It  consists  of  a  laminated,  dark  gray  sandstone  weathered  to  yellow 
brown,  dark  gray  shale  with  limestone  strata  or  limy  concretions  and 
minor  strata  of  micaceous,  carbonaceous,  brown  sandstone  interbedded 
with  it.    The  only  fossils  found  in  it  were  Chione  varians  (Gabb)  and 
a  Pecten,  n.  sp.,  obtained  at  University  of  California  Location  783, 
three-quarters  of  a  mile  west  of  Lower  Lake.     Structurally  the  Chico 
is  folded  in  many  minor  plications  and  shows  complex  twisting  and 
faulting.     The  lower  Martinez  can  be  readily  distinguished  from  the 
underlying   Chico   by   great   differences   in   lithology   and   structure. 
The  lower  Martinez  consists  of  medium-grained,  hard  sandstone  con- 
taining grains  of  hornblende,  quartz  and  biotite.      It  has  a  peculiar 
velvety  luster  which  may  be  due  to  secondary  silica.    Structurally  the 
Martinez  is  not  faulted,  nor  has  it  been  folded  and  contorted  like 
the  underlying  Chico.    In  the  bed  of  Herndon  Creek  near  the  contact 
with  the  Chico  it  has  a  strike  of  N  50°  W,  while  that  of  the  Chico  is 
N  65°  W.    The  basal  Martinez  appears  to  overlie  the  Chico,  Knoxville 
and  Franciscan  indifferently  and  without  doubt  it  is  unconformable 
upon  all  of  them.    Differences  in  strike,  in  the  amount  of  folding  and 
crushing,  in  fauna  and  in  areal  distribution  between  the  Martinez  and 
the  underlying  Chico,  Knoxville  and  Franciscan  lead  us  to  the  above 
conclusion.     The  great  thickness  of  the  Martinez  in  this  region   is 
noteworthy.     A  measured  section  down  Herndon   Creek  shows  that 
the  basal  Martinez  consists  of  1200  feet  of  medium  gray  sandstone. 
This  is  overlain  by  500  feet  of  fine,  massive,  tan-colored  sandstone 
flecked  with  black  grains.     No  exposures  of  Martinez  are  found  for 


94  University  of  California  Publications  in  Geology          [VOL.  8 

one  thousand  feet,  but  Cache  Lake  beds  of  fine-grained  argillaceous 
sandstone  and  gray  sandstone  with  gray  shale,  strike  N  30°  E  and 
dip  20°  E,  unconformably  overlie  the  Martinez.  An  outcrop  of 
Martinez  one  hundred  feet  thick  which  yielded  Pholadomya  nasuta, 
Dentalium  cooperi,  Schizaster  lecontei,  and  Modiolus  ornatus  is  next 
found.  These  beds  are  composed  of  fine-grained,  massive  sandstone 
dipping  northward.  Five  hundred  feet  down  the  creek  from  this  point 
similar  beds  about  one  hundred  feet  thick  appear  with  a  high  dip  to 
the  north.  Even  in  this  partial  section  we  have  at  least  3500  feet  of 
Martinez  strata  present.  That  this  is  not  complete  is  seen  when  we 
study  the  upper  portion  of  the  Martinez  on  the  other  limb  of  the 
syncline.  At  least  three  hundred  to  five  hundred  feet  of  gray-green 
shales  lie  above  the  last-mentioned  fine-grained  tan  sandstone  at  this 
place.  A  minimum  estimate  is  between  thirty-eight  hundred  and  four 
thousand  feet  for  the  total  thickness  of  these  beds. 

A  small  area  of  the  Cache  Lake  formation  which  was  originally 
described  by  Becker24  is  found  unconformably  overlying  the  Martinez 
north  and  east  of  Lower  Lake  village.  It  is  best  observed  in  Herndon 
Creek,  where  its  fine-grained,  argillaceous  sandstones  and  gray  shales 
have  a  dip  of  15°-20°  E.  Near  the  mouth  of  Herndon  Creek  are  seen 
about  two  hundred  feet  of  a  coarse  gray  tuff  which  appears  to  be  the 
uppermost  portion  of  these  fresh-water  beds.  The  tuff  beds  are  folded 
in  an  asymmetric  syncline,  the  south  limb  of  which  dips  60°  to  the 
north.  The  total  thickness  of  these  beds  appears  to  be  from  seven 
hundred  to  eight  hundred  feet.  The  Cache  Lake  beds,  like  the  Mar- 
tinez, are  cut  off  on  the  west  by  andesitic  lava  flows  which  appear  to 
overlie  them.  According  to  Stearns,  who  determined  the  fresh-water 
fossils  found  in  these  beds  by  Becker,  they  are  of  Pliocene  age. 

Rocks  of  Tejon  age  occupying  an  elliptical  area  two  and  one-half 
miles  long  on  the  eastern  portion  of  the  Lower  Lake  syncline  rest 
upon  the  Martinez.  Coarse  gray  to  white,  conglomeritic  concretionary 
sandstone  which  gives  rise  to  bluffs  make  up  practically  its  entire 
thickness,  1100  to  1200  feet.  It  is  lithologically  distinct  from  the 
uppermost  Martinez  which  consists  of  thin-bedded,  fine-grained,  green- 
gray  sandstone  with  green  shales..  No  sharp  contacts  between  the 
Martinez  and  Tejon  were  found  and  hence  their  relations  to  one 
another  are  not  entirely  clear.  The  dips  in  the  Tejon  vary  from  30° 
to  35°,  while  those  of  the  Martinez  are,  on  the  whole  much  higher. 


24  Becker,  G.  F.,  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope, 
Monograph  13,  U.  S.  Geological  Survey,  pp.  219-221,  1888. 


1914]      DicJcerson:  Fauna  of  the  Martinez  Eocene  of  California          95 

This,  taken  together  with  a  distinct  faunal  break  and  abrupt  litho- 
logical  change,  leads  us  to  believe  that  a  considerable  time-interval 
elapsed  between  the  deposition  of  these  two  groups  of  the_  Eocene. 
Only  two  fossil  localities  were  found  in  the  Tejon.  The  following 
fauna  was  found  at  University  of  California  Locality  785 : 


Crassatellites  cf.  uvasana  (Gabb) 
Dosinia  elevata  Gabb 
Spisula,  n.  sp. 
Meretrix  ovalis  Gabb 
Meretrix,  sp. 
Meretrix  hornii  Gabb 
Psammobia  hornii  (Gabb) 
Solen  parallelus  Gabb 
Tapes  cf.  cretacea  Gabb 
Tellina  longa  Gabb 
Bulla  hornii  Gabb 
Cancellaria  marysvillensis  Dicker- 
son 


Drillia,  n.  sp. 

Fusus  californicus  Gabb 

Fusus,  sp. 

Lunatia  hornii  Gabb 

Naticina  obliqua  Gabb 

Neverita  globosa  Gabb 

Surcula  (surculites)  cf.  sinuata 

Gabb 

Tritonium  whitneyi  Gabb 
Whitneya  ficus  Gabb 
Serpula,  sp. 
Shark  (?)  tooth 


Of  the  forms  listed  above,  Dosinia  elevata  Gabb,  Meretrix  ovalis 
Gabb,  Solen  parallelus  Gabb,  Tellina  longa  Gabb,  Bulla  hornii  Gabb, 
Cancellaria  marysvillensis  Dickerson,  Fusus  californicus  Gabb,  Nati- 
cina obliqua  Gabb,  Neverita  globosa  Gabb,  Tritonium  whitneyi  Gabb, 
and  Whitneya  ficus  Gabb  are  as  far  as  known  entirely  typical  of  the 
Tejon. 

FAUNA  OF  THE  MARTINEZ  AT  LOWER  LAKE 

The  preservation  of  the  fossils  in  the  Martinez  near  Lower  Lake  is 
better  than  at  most  localities  and  their  abundance  at  a  few  localities 
make  the  collections  from  this  place  particularly  valuable.  Most  of 
the  fossils  were  found  in  strata  approximately  five  hundred  to  a 
thousand  feet  above  the  base  of  this  group.  The  following  list  of 
species  collected  from  these  beds  appear  to  belong  in  the  same  faunal 
zone : 


LIST  OF  SPECIES 


Loc. 
784 


Loc. 
790 


Listed  by 
Stanton 


Stylophora(?),  sp 

Flabellum  remondianum  Gabb 

Cidarid,  sp 

Cidaris  merriami  Arnold  X 

Membranipora(?),  sp 

Rhynconella(?),  sp X 

Terebratulina  tejonensis  Stanton  x 

Crassatellites  unioides   (Stanton)   


96 


University  of  California  Publications  in  Geology          [VOL.  8 


LIST  OF  SPECIES — (Continued) 


Loc. 

784 


Crassatellites  grandis(?)  (Gabb)  

Cucullaea  mathewsonii  Gabb  

Glycimeris  veatchii,  var.  major  (Stanton) 

Leda  gabbi  Conrad  

Leda  alaeformis  (Gabb)  

Leda  packardi,  n.  sp 

Lima  multiradiata  Gabb 

Lucina,  sp 

Lucina  turner!  Stanton 

Martesia( ?),  sp 

Mactra(?)  tenuissima  Gabb  

Macrocallista(?),  packi,  n.  sp 

Meretrix  stantoni,  n.  sp : 

Meretrix  dalli,  n.  sp 

Modiolus  ornatus  Gabb)   

Ostraea  buwaldana,  n.  sp 

Ostraea  weaver!,  n.  sp 

Perna,  sp 

Pecten,  sp 

Paphia(?)  clarki,  n.  sp 

Plicatula  ostreaformis  Stanton  

Phacoides  quadrata,  n.  sp 

Psammobia  hornii  (Gabb)  

Solen  parallelus  Gabb  

Solen,  sp 

Tapes  cf.  quadrata  Gabb  

Tellina(?)  undulifera  Gabb  

Tellina  kewi,  n.  sp 

Tellina  herndonensis,  n.  sp 

Tellina  packardi,  n.  sp 

Tellina  perrini,  n.  sp 

Tellina  cf.  parilis  Gabb  

Tellina,  sp.,  a  

Tellina  aequalis  Gabb  

Tellina,  sp.,  b  

Venericardia  planicosta  Lam 

Venus(?),   sp 

Yoldia  gesteri,  n.  sp x 

Ampullina  striata  Gabb  

Acmaea  martinezensis,  n.  sp 

Actaeon,  sp 

Amauropsis  cf.  martinezensis,  n.  sp x 

Brachysphingus  liratus  Gabb  x 

Cerithiopsis  alternata  Gabb  

Cylichna  costata  Gabb  

Cylichna,  sp 

Cypraea  bayerquei  Gabb  

Dentalium  cooperi  Gabb  


Loc. 
790 

X 
X 

x 
x 

X 
X 

x 


Listed  by 
Stanton 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California          97 

LIST  OF  SPECIES — (Continued) 

Loc.          Loc.        Listed  by 
784  790         Stanton 

Dentalium  stramineum  Gabb  x  x 

Dentalium,  sp X _.... 

Fusus  dumblei,  n.  sp x 

Galerus  excentricus  Gabb  x  x 

Heteroterma  gabbi  Stanton  ....  x 

Heteroterma,  sp x 

Heteroterma  striata  Stanton  x  ....  x 

Lunatia  hornii  Gabb  x  x  x 

Lunatia  cf.  nuciformis  Gabb  x 

Lunatia,  sp.,  a X 

Natica  (Gyrodes)  lineata,  n.  sp x  x 

Neptunea,  sp ....  x 

Natica,  sp.,  e  ....  x 

Patella,  sp ....  x 

Perissolax  tricarnatus  Gabb  x 

Einginella  pinguis  Gabb  X  x 

Siphonalia(?)  lineata  Stanton  X  x  x 

Seraphs  (?)  thompsoni,  n.  sp x 

Tritonium  buwaldi,  n.  sp X 

Turritella  pachecoensis  Stanton  ....  x 

Turritella  martinezensis(?)   Gabb  ....  x 

Turritella  infragranulata  Gabb  ....  x 

Urosyca  caudata  Gabb  x  x  x 

Urosyca  robusta  Weaver  x 

Shark  tooth  x 

A  comparison  of  the  fauna  listed  above  with  that  of  our  reference 
zones  at  Mount  Diablo  and  the  type  locality  brings  out  at  once  a 
striking  resemblance  between  it  and  that  of  the  basal  beds  north  of 
Mount  Diablo.  Both  are  inshore  deposits.  This  is  shown  both  by  the 
nature  of  the  sediments  which  constitute  them  and  the  character  of 
the  included  faunas.  The  ratio  of  gastropods  to  pelecypods  is  about 
2:41/2  in  the  above  fauna.  Not  only  is  this  true  in  the  number  of 
different  species  but  a  census  shows  that  pelecypods  flourished  in  the 
waters  of  the  shallow  Martinez  sea  of  this  time  better  than  the  gastro- 
pods. Out  of  this  total  fauna  of  sixty-four  species,  the  following 
species  have  not  been  found  in  the  Meretrix  dalli  zone  north  of  Mount 
Diablo  or  in  higher  strata: 

Stylophora(?),  sp.  Tellina  cf.  parilis  Gabb(?) 

Rhynconella,  sp.  Venus (?),  sp. 

Ostrea  buwaldana,  n.  sp.  Yoldia  gesteri,  n.  sp. 

Pecten,  sp.  Martesia(f),  sp. 

Plicatula  ostreaf  ormis  Stanton  Aemaea  martinezensis,  n.  sp. 

Phacoides  quadrata,  sp.  Seraphs(?)  thompsoni,  n.  sp. 

Tellina  packardi,  n.  sp.  Tritonium  buwaldi,  n.  sp. 
Tellina  perrini,  n.  sp. 


98  University  of  California  Publications  in  Geology          ['VOL.  8 

Of  these  most  are  new  species,  the  types  of  which  in  several  cases 
are  the  only  ones  thus  far  found.  The  ratio  of  Tejon  forms  in  this 
fauna  is  about  15  to  80  while  that  of  the  Meretrix  dalli  beds  is  14 
to  80.  Most  of  the  Tejon  forms  which  range  downward  belong  to  the 
same  species  in  both  cases.  In  other  words,  they  are  the  persistent 
forms.  It  is  thus  apparent  that  this  fauna  is  nearly  the  equivalent 
of  the  Meretrix  dalli  zone  in  the  area  north  of  Mount  Diablo.  Since 
it  is  found  five  hundred  to  a  thousand  feet  above  the  base  of  the 
Martinez  at  Lower  Lake,  it  is  evident  that  we  have  strata  at  Lower 
Lake  which  are  considerably  lower  than  any  other  Eocene  known  in 
the  state.  The  writer  is  inclined  to  believe  that  the  fauna  above  listed 
is  slightly  lower  than  that  of  the  Meretrix  dalli  zone  of  the  Mount 
Diablo  region.  This  impression  is  gathered  in  part  from  the  aspect 
of  the  new  forms  mentioned  above  and  the  possible  occurrence  of  two 
Tellinas  which  may  occur  in  the  Chico.  The  specimen  listed  as 
Tellina  cf.  parilis  Gabb  seems  to  be  identical  with  Gabb's  description 
and  figure.  The  specimens  of  Tellina  herndonensis,  n.  sp.,  agree  with 
one  of  Gabb's  figures  of  T.  hoffmaniana  in  volume  I  of  the  Palae- 
ontology of  California,  but  he  unfortunately  confused  this  species. 
The  figure  in  volume  I  does  not  agree  with  his  figure  for  this  species  in 
volume  II.  Rhynconella(f),  sp.,  also  lends  a  Cretaceous  aspect  to  the 
fauna.  The  absence  of  Pholadomya  nasuta  Gabb  from  the  lower  zone 
and  its  presence  in  strata  a  thousand  feet  above  is  noteworthy.  Of 
all  forms  in  the  Martinez  Pholadomya  nasuta  is  one  of  the  most  widely 
ranging,  both  stratigraphically  and  geographically,  and  we  should 
expect  to  find  it  in  a  Martinez  fauna  as  well-preserved  as  this. 

The  upper  and  middle  portions  of  the  Martinez  at  Lower  Lake  are 
but  sparingly  fossiliferous.  Schizaster  lecontei  Merriam,  Turritella 
pachecoensis  Stanton,  Ostrea  weaveri,  n.sp.,  which  were  found  at 
University  of  California  Locality  782,  are  the  only  fossils  which  were 
found  in  the  middle  of  the  Martinez  section  exposed  at  Lower  Lake. 

The  following  species  were  obtained  from  the  upper  beds : 

FAUNA  OP  THE  UPPER  MARTINEZ 

Loc.        Loc.        Loc.        Loc.        Loc. 
788          779          782          787          780 

Schizaster  lecontei  Merriam  x        

Cucullaea  mathewsonii  Gabb  x         

Leda  gabbi  Conrad  x 

Leda  alaeformis  (Gabb)   x 

Leda  packardi,  n.  sp ....  x 

Modiolus  ornatus  (Gabb)  x         


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  Calif  ornia          99 
FAUNA  OF  THE  UPPER  MARTINEZ — (Continued) 

Loc.        Loc.        Loc.        Loc.        Loc. 

788         779         782         787         780 

Meretrix(f),  sp ....         ....  x 

Ostrea  weaver!,  n.  sp x         — ^ — 

Ostrea,  sp x         

Phacoides,  sp x 

Psammobia  cylindrica,  n.  sp X 

Pholadomya  nasuta  Gabb  x         ....  x 

Paphia  cf.  clarki,  n.  sp ....         ....  x 

Solen  stantoni  Weaver  x 

Tellina,  sp.,  indet 

Dentalium  cooperi  Gabb  x          x 

Fusus  cf.  flexuosus  Gabb  x 

Natica,  sp x 

Turritella  pachecoensis  Stanton  x          x 

Turritella  infragranulata  Gabb  x          x         

All  of  these  localities  are  over  3200  feet  above  the  base  and  may 
therefore  be  regarded  as  representing  the  uppermost  Martinez  of  this 
region.  Although  they  contain  but  one  form,  Solen  stantoni,  char- 
acteristic of  the  upper  horizon  at  the  type  locality  of  the  Martinez 
the  absence  of  many  of  the  species  characteristic  of  the  middle  and 
lower  zones  is  noteworthy.  While  the  evidence  is  meager,  the  strata 
3200  feet  or  more  above  the  base  are  tentatively  correlated  with  the 
uppermost  zone  of  the  type  section.  Localities  787  and  780  are 
probably  about  two  hundred  feet  below  the  base  of  the  Tejon,  so  that 
their  faunas  represent  the  very  youngest  Martinez  in  the  whole 
Lower  Lake  area. 

MARTINEZ  OF  SAN  MATEO  COUNTY 

A  collection  of  fossils  from  a  formation  in  the  vicinity  of  San 
Pedro  Point  was  referred  to  the  writer  for  determination  and  study 
by  Professor  A.  C.  Lawson  and  Professor  J.  C.  Merriam.  The  collec- 
tion was  made  by  Messrs.  G.  D.  Gerson,  R.  W.  Pack,  and  E.  Behr 
during  the  past  four  years. 

Professor  A.  C.  Lawson,25  in  "A  Sketch  of  the  San  Francisco 
Peninsula, ' '  first  described  these  beds  as  follows : 

(1)     A  basal  formation  of  conglomerates,  coarse  grits,  sandstones,  shales, 

and  argillaceous  limestones,  exposed  in  the  vicinity  of  San  Pedro  Point 

The  base  of  the  series  is  exposed  in  the  vicinity  of  San  Pedro  Point.  Here  the 
basal  detrital  rocks  mantle  over  the  crest  of  the  Montara  granite  ridge.  A 
little  to  the  north  of  the  ridge,  on  the  slope  to  San  Pedro  Valley,  the  strata 
are  somewhat  complexly  folded.  They  have  the  appearance  of  having  been 

25  Lawson,  A.  C.,  A  Sketch  of  the  San  Francisco  Peninsula,  15th  Ann.  Kept. 
U.  S.  Geol.  Surv.,  pp.  416,  436,  1894. 


100  University  of  California  Publications  in  Geology          [VOL.  8 

crowded  up  against  the  granite  and  of  having  been  sharply  folded  against  it. 
The  result  has  been  to  throw  the  strata  into  anticlines  and  synclines,  some  of 
which  have  reversed  dips.  The  stratification  in  this  basal  formation  is  more 
distinct  and  even  than  anywhere  else  in  the  fragmental  portions  of  the  series. 
As  we  follow  the  contact  of  the  series  against  the  granite  slopes  of  Montara 
Mountain  from  San  Pedro  Point  southeastward,  it  becomes  apparent  that  these 
basal  beds  have  been  dropped  out  of  sight  by  a  fault  parallel  to  the  axis  of 
the  ridge,  so  that  higher  and  higher  horizons  of  the  series  come  against  the 
granite.  If  the  basal  formations  of  San  Pedro  Point  were  all  coarse-grained, 
it  might  be  supposed  that  we  had  to  deal  simply  with  a  case  of  transgression 
of  sediment  from  northwest  to  southeast.  But  a  portion  of  the  basal  formation 
is  a  fine,  bluish-black  clay-shale.  While,  therefore,  it  is  possible  that  a 
portion  of  the  contact  of  the  granite  against  higher  and  higher  portions  of 
the  series  may  be  due  to  transgression,  it  seems  more  probable  that  the  greater 
part  of  it  is  due  to  faulting.  It  is  also  possible  that  the  rocks  classed  here 
as  the  basal  detrital  formation  of  San  Pedro  Point  may  be  an  older  series 
separated  from  the  Franciscan  series  by  an  unconformity.  This  suggestion 
has  little  to  support  it  at  present  beyond  the  fact  that  the  relations  of  these 
rocks  to  the  San  Francisco  sandstone  are  not  clear,  and  that  the  latter  very 
commonly  contains  fragments  of  black  shale  similar  to  that  of  San  Pedro  Point. 
But  whether  transgression  or  unconformity,  or  both,  occur,  the  fault  is  present. 

Mr.  G.  D.  Gerson  again  investigated  these  beds  in  the  spring  of 
1907  and  found  the  fossil  locality  from  which  the  main  collection  came. 

The  section  along  the  sea  cliff  from  Devil's  Slide  to  Tobin  Station, 
a  quarter  of  a  mile  north  of  San  Pedro  Point,  gives  the  following 
sequence  of  beds : 

(4)   Soft  tan-colored  sandstone  and  thin-bedded  shale,  200-300  feet. 

(3)  Coarse  sandstone  and  conglomerate,  200-300  feet. 

(2)   Thin-bedded,  fine-grained,  gray  sandstone  and  black   shale  with 

black  limestone,  300-400  feet. 
(1)  Basal  conglomerate  and  sandstone  resting  on  Montara  granite  at 

Devil's  slide,  300-400  feet. 
Total,  1200-1400  feet. 

The  basal  conglomerate  (1)  appears  only  at  Devil's  Slide  and  (4), 
the  upper  sandstone  and  shale,  only  in  the  center  of  the  section. 
There  are  at  least  two  or  three  folds  with  some  faulting  in  the  cliff 
section.  The  fossils  occur  in  (3),  the  coarse  sandstone  and  conglom- 
erate, at  the  head  of  a  small  canon  south  of  Tobin  Station,  and  east 
of  San  Pedro  Point  at  an  elevation  of  350  feet.  This  coarse  sand- 
stone bears  a  peculiar  relation  to  the  underlying  shales  and  sandstones. 
An  unconformity  is  suggested,  but  the  strata  are  faulted  only  a  short 
distance  away — one  or  two  hundred  feet  south — and  the  relation  of 
the  two  may  be  due  to  this  movement.  Large  boulders  of  granite  in 
coarse  sandstone  and  conglomerate  occur  in  an  exposure  along  the 
road  from  San  Pedro  to  Half  Moon  Bay.  Possibly  they  are  blocks 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        101 


from  a  sea  cliff  buried  in  the  sands  of  the  beach  of  that  time.  This 
evidence  seems  to  lend  support  to  the  interpretation  of  an  uncon- 
formity rather  than  a  fault  as  the  best  explanation  of  the  relations 
of  the  second  and  third  beds. 

The  fossils  were  found  in  the  lower  portion  of  (3),  the  coarse 
sandstone  and  conglomerate  described  above.  The  matrix,  a  coarse 
sandstone,  does  not  preserve  the  details  of  the  fossils  well.  The  rock 
is  exceedingly  friable  and,  although  shell  impressions  are  abundant, 
it  is  difficult  to  discern  even  the  generic  characters. 

Below  is  a  list  of  the  fauna  from  these  beds: 


Flabellum,  sp. 

ParacyathusC?),  sp. 

Cidaris,  sp. 

Terebratulina  cf.  tejonensis  Stan- 
ton 

Cardium  cf.  cooperi  Gabb 

Cucullaea  cf.  mathewsonii  Gabb 

Dosinia  cf .  lawsoni,  n.  sp. 

Glycimeris,  sp. 

Glycimeris  cf.  veatchii  var.  major 
Stanton 

Macrocallista  (?)  packi,  n.  sp. 

Meretrix  stantoni,  n.  sp. 

Modiolus  cf.  bakeri,  n.  sp. 

Ostrea  buwaldana,  n.  sp. 

Phacoides  diaboli,  n.  sp. 

Phacoides  quadrata,  n.  sp. 

Semele(?),  sp. 

Tapes(?)  quadrata  Gabb 

Teredo,  sp. 

Venus (?),  sp. 

Venericardia,  sp. 


Amauropsis(?),  sp. 

Alaria,  sp. 

Chlorostoma(?),  sp. 

Cylichna  costata  Gabb 

Dentalium,  sp.  striated 

Dentalium  cooperi  Gabb 

Discohelix,  sp. 

Fissurella,  sp. 

Galerus  excentricus  Gabb 

Hipponyx,  sp. 

Natica,  sp.,  a 

Natica  (?)  sp.,  fc,  spiral  lined 

Patella,  sp. 

Einginella  cf.  pinguis  Gabb 

Spiroglyphus(?),  sp. 

Tritonium  martinezensis,  n.  sp. 

Tritonium,  sp.,  a 

Turritella,  sp. 

Turritella  cf.  pachecoensis  Stanton 

Urosyca  cf.  caudata  Gabb 

Crustacean  fragments 


Nearly  all  the  genera  represented  occur  in  the  Martinez  Group 
and  one,  Uroscyca,  appears  to  be  restricted  to  it. 

Macrocallista(f)  packi,  n.  sp.,  Meretrix  stantoni,  n.  sp.,  Modiolus 
bakeri,  n.  sp.,  Phacoides  quadrata,  n.  sp.,  Cidaris,  sp.,  Tritonium  mar- 
tinezensis, n.  sp.,  Urosyca  caudata,  Galerus  excentricus,  Cylichna 
costata,  and  Dentalium  cooperi  occur  in  the  basal  Martinez  north  of 
Mount  Diablo  or  in  the  Martinez  of  Lower  Lake.  Of  these  the  first 
seven  are  characteristically  Martinez,  the  last  four  range  upward  into 
the  Tejon,  and  the  last  two  downward  into  the  Chico.  Several  of  the 
others  listed  appear  to  be  close  to  Martinez  forms,  but  they  are  too 
poorly  preserved  to  be  specifically  determined.  Several  of  these  species 
are  new,  but  none  of  them  represent  characteristically  Cretaceous 


102  University  of  California  Publications  in  Geology          [VOL.  8 

genera.  The  beds  in  which  the  fossils  occur  are  of  Eocene  age  and 
of  the  Martinez  stage.  They  possibly  represent  a  lower  phase  than 
has  been  recognized  in  the  type  locality  of  the  Martinez  or  in  the 
region  north  of  Mount  Diablo. 

Fossils  had  previously  been  found  in  the  same  formation  at  Mon- 
tara  Mountain  by  Merriam  and  Ransome,  and  a  brief  note  concerning 
their  occurrence  was  given  by  Lawson26  in  "A  Sketch  of  the  Geology 
of  the  San  Francisco  Peninsula": 

On  the  northeast  slope  of  Montara  Mountain,  on  the  crest  of  Whiting 
Eidge,  a  number  of  imperfect  fossils  were  found.  .  .  .  The  matrix  in  which 
they  occur  is  sandstone.  These  fossils  were  submitted  to  Mr.  Stanton,  who 
kindly  prepared  the  following  statement  concerning  them:  "The  fossils  are 
nearly  all  casts  of  small  Lamellibranchia,  usually  showing  some  of  the  features 
of  the  external  surface  and  so  few  of  their  characteristics  that  most  of 
them  can  not  be  determined  even  generically.  Several  specimens,  however, 
that  retain  impressions  of  the  hinge,  belong  to  the  Arcidae,  and  some  of  these 
seem  referable  to  Pectunculus,  a  genus  that  ranges  from  Lower  Cretaceous  to 
the  present  time.  One  small  imperfect  cast  has  the  form  of  Opis,  and  if  we 
could  be  certain  that  it  is  that  genus  it  would  fix  the  age  as  Mesozoic,  with 
the  probabilities  in  favor  of  Lower  Cretaceous  or  Jurassic.  On  the  other  hand 
there  is  a  fragment  showing  the  imprint  of  a  small  part  of  the  surface  of  a 
shell  that,  in  the  ornamentation,  is  very  much  like  some  of  the  late  Tertiary 
and  recent  species  of  Venus.  These  notes  are  sufficient  to  show  that  there  are 
no  characteristic  forms  recognizable  in  the  collection  that  are  decisive  of  its 
Mesozoic  or  Cenozoic  Age.  There  is  nothing  among  them  that  suggests  the 
Palaeozoic.  It  is  hoped  that  these  beds  may  yield  to  future  search  some  better 
preserved  forms  which  will  decide  their  age. ' ' 

Professor  Lawson  informs  me  that  these  beds  are  directly  con- 
nected with  those  of  San  Pedro  Point,  so  that  they  too  are  to  be 
regarded  as  Martinez  Eocene. 


EOCENE  (?)  OF  THE  SANTA  CRUZ  QUADRANGLE 

The  fauna  from  this  locality  which  was  listed  above  in  the  review 
of  the  literature  was,  at  the  time  of  its  discovery,  so  unique  that  its 
stratigraphic  position  was  questioned.  T erebratulina  tejonensis  Stan- 
ton  was  the  only  previously  described  species  listed  in  the  entire  fauna. 
The  species  which  was  identified  as  Terebratulina  tejonensis  by  Arnold 
differs  slightly  from  T.  tejonensis.  It  is  broader  in  outline  and  the 
ribs  are  more  numerous.  A  cidarid  spine  is  found  in  the  basal  Mar- 
tinez which  resembles  Cidaris  merriami  Arnold,  but  it  has  only  ten 


26  Lawson,  A.  C.,  op.  cit.,  p.  445,  1894. 


1914]      Dicker  son :  Fauna  of  the  Martinez  Eocene  of  California        103 

ribs  instead  of  thirteen  or  fourteen.  There  is  really  no  good  evidence 
to  warrant  placing  this  fauna  in  the  Martinez.  Until  it  has  been 
recognized  with  certainty  at  some  other  locality,  or  a  better  fauna  has 
been  obtained  at  the  original  locality,  its  age  will  remain  in  doubt. 


SUMMARY  OF  MARTINEZ  STRATIGRAPHY 

The  greatest  thickness  of  strata  of  Martinez  age  yet  recognized  in 
California  is  exposed  near  the  town  of  Lower  Lake.  These  strata 
probably  represent  the  greatest  length  of  time  as  well.  The  seven 
hundred  feet  of  strata  beneath  the  first  fossiliferous  horizon,  the 
Meretrix  dalli  zone,  are  older  than  any  strata  known  elsewhere  in  the 
state,  as  the  Meretrix  dalli  zone  appears  to  represent  a  slightly  earlier 
period  of  Martinez  time  than  this  same  zone  at  the  base  of  the 
Martinez  in  the  area  north  of  Mount  Diablo.  The  Martinez  at  San 
Pedro  Point,  San  Mateo  County,  may  be  the  equivalent  of  the  Meretrix 
dalli  zone  of  the  Lower  Lake  Martinez.  The  Trochocyathus  zitteli  and 
Solen  stantoni  zones  are  not  easily  recognized  at  Lower  Lake,  but  they 
both  appear  to  be  present. 

The  2400  feet  of  strata  at  Benicia  is  probably  the  equivalent  of  the 
upper  3300  feet  of  strata  at  Lower  Lake.  The  Martinez  of  the  type 
locality  is  probably  equivalent  to  the  upper  2600-3000  feet  of  the 
Lower  Lake  Martinez.  The  Martinez  at  Selby  Smelter  represents  only 
the  middle  portion  of  the  Martinez,  the  Trochocyathus  zitteli  zone. 
The  Martinez  north  of  Mount  Diablo  is  equivalent  to  most  of  the 
Meretrix  dalli  zone  of  the  Lower  Lake  strata  and  to  the  Trochocyathus 
zitteli  zone  of  the  type  locality.  The  Solen  stantoni  zone  appears  to 
be  lacking  in  this  section  and  is  probably  represented  in  the  uncon- 
formity between  the  overlying  Tejon  and  the  Martinez  at  this  point. 
The  accompanying  diagram  presents  the  relations  between  the  strata 
of  various  localities  graphically  (see  fig.  5).  The  sections  given  below 
refer  to  their  respective  columns  in  figure  5. 

I.  SECTION  AT  POINT  SAN  PEDRO,  SAN  MATEO  COUNTY,  CALIFORNIA 

Feet 

f  (5)   Soft  tan  sandstone  and  shale  300 

Martinez  I    (4)   Coarse-grained  sandstone  and  conglomerate  ] 

Eocene     ^  (3)  Fossiliferous  beds  j     30( 

(2)  Fine-grained  sandstone,  limestone  and  black  shale  400 

(1)  Coarse  sandstone  and  conglomerate  400 


Eocene  (!)•< 


Total  ..  1400 


104 


University  of  California  Publications  in  Geology          [VOL.  8 


Martinez 
Eocene 


II.  SECTION  AT  BENICIA,  CALIFORNIA 

Feet 
(7)   Gray-green  shales  and  thin  bedded  sandstones  1 

(6)  Solen  stantoni  beds  .' L  1400 

(5)  Gray-green  shales  and  thin  bedded  sandstones  J 

(4)  Trochocyathus  zitteli  beds  

(3)  Brown  sandstones  

(2)  White  shale   

(1)  Conglomerate  and  sandstone 20 


900 
50 


Total  ..  ..  2370 


III.  SECTION  AT  LOWER  LAKE,  LAKE  COUNTY,  CALIFORNIA 

Feet 
(10)   Gray  shales  and  thin  bedded  sandstones  1 

(9)   Solen  stantoni  beds  >. J     70C 

(8)  Gray  shales  and  thin  bedded  sandstones  1 

(7)   Massive,  tan  sandstone  L  1600 

Martinez       (6)   Trochocyathus  zitteli  beds  J 

Eocene         (5)  Massive,  tan  sandstone  ) 

(4)  Fine-grained,  massive,  tan  sandstone  f 

(3)  Medium-grained,  gray,  sandstone  500 

(2)  Meretrix  dalli  beds ) 

(1)  Medium-grained,  gray  sandstone C 

Total  4000 

IV.  SECTION  NEAR  MARTINEZ  AT  TYPE  LOCALITY 

Feet 
(7)  Solen  stantoni  beds 1 

(6)  Gray  sandstone  I  1000 

(5)  Gray-green,  glauconitic  sandstone  J 

(4)  Trochocyathus  zitteli  beds  ) 

Martinez        ,    Har(J     /     gandstone  300 

Eocene 

(3)  Gray-green,  glauconitic  sandstone  | 

Trochocyathus  zitteli  beds  j 

(2)  Gray  sandstone  with  lenses  of  limestone 300 

(1)  Conglomerate  50 

Total  1700 

V.  SECTION  NEAR  SELBY  SMELTER,  CARQUINEZ  STRAITS 

Feet 

C  (3)   Gray-green,  foraminiferal  shale  500 

;ZJ    (2)  Trochocyathus  zitteli  beds  ) 

[   (1)   Gray-green,  glauconitic  sandstone  J 


Total  ..  700 


3 

OTQ' 


Cb  VJ 


06        NJ 


106 


University  of  California  Publications  in  Geology          [VOL.  8 


VI.  SECTION  NORTH  OF  MOUNT  DIABLO 


Martinez 
Eocene 


Feet 
300 


(5)   Gray-green  shale 

(4)   Gray-green,  glauconitic  sandstone  1 

Trochocyathus  zitteli  beds  ( 

(3)  Fine-grained,  gray  sandstone 200 

(2)   Shales  and  sandstones  100 

(1)  Brown,  conglomeritic  sandstone  

Meretrix  dalli  beds  ... 


50 


Total  ..  700 


SUMMARY  OF  MARTINEZ  FAUNA 

The  table  given  below  indicates  the  occurrence  and  distribution  of 
the  forms  which  are  found  in  the  Martinez.  The  local  occurrence  of 
each  species  is  given  in  the  first  major  column  and  the  range  of  the 
species  is  indicated  in  the  second.  Three  major  faunal  zones  are 
recognized  in  the  Martinez :  a  lower,  the  Meretrix  dalli  zone ;  a  middle, 
the  Trochocyathus  zitteli  zone ;  and  an  upper,  the  Solen  stantoni  zone. 
The  Meretrix  dalli  zone  is  typically  represented  in  the  Martinez  north 
of  Mount  Diablo,  while  the  Trochocyathus  zitteli  and  the  Solen  stan- 
toni zones  were  first  recognized  at  the  type  locality  near  Martinez. 
The  type  locality  may  be  regarded  as  the  type  locality  of  these  last 
two  zones  as  well.  The  sections  given  above  refer  to  their  respective 
columns  in  figure  5. 


LIST  OF  MARTINEZ  SPECIES 


MARTINEZ  LOCALITIES 


RANGE  OF  SPECIES 


Anomalina  ammonoides  Reuss 

Martinez  N.  of  1 
Mount  Diablo 

Type  locality, 
*  Benicia,  Selby 

m 

«                                                             J3 

•g    g         S     si 

h              ?                                      to   g              0    N 
te                  C             o           §.„           «"3 

x 

J{  1 

Stylophora(  ?),  sp. 

X 

x 

Flabellum  remondianum  Gabb  

X 

X 

X         ....        X?           X           X 

x 

Flabellum.  sp. 

x 

x 

Paracyathus(  ?),  sp  

X 

x 

Trochocyathus  zitteli   (Merriam)   

X 

X 

x 

Schizaster  lecontei  Merriam 

X 

x 

X                         XXX 

x 

Cidaris(?),  sp.,  c  

X 

x 

Cidaris(f),  sp.,  a  

X 

x 

x 

X 

CidarisC?),  sp.,  d  ... 

X 

X 

1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        107 

LIST  OF  MARTINEZ  SPECIES — (Continued) 

MARTINEZ  LOCALITIES  RANGE  OF  SPECIES 


>»1      |i 

IS    Is 

!  i      i§  li 

ll 

3g      «.s 

II  '  II 

O             c8  O             c;          'o  S           *-«  +* 

1! 

J 

Bhynconella(?),   sp  

x      

X 

.... 

Terebratulina  tejonensis  Stanton  

x 

X         

x 

.... 

Membranipora,  sp  

X        

X 

.... 

Avicula  cf.  pellucida  Gabb  

x 

X 

.... 

Anatina(?),  sp  

X 

X 

.... 

.... 

Astarte(f),  sp  

X 

X 

Cardium  cooperi  Gabb  

X           X 

XXX 

X 

.... 

Cardium  cf.  cooperi  Gabb  

X           X           X           X 

X 

x 

Cardita  veneriformis  Gabb  

X 

x 

.... 

Cucullaea  mathewsonii  Gabb  

X           X 

X         X           X 

X 

.... 

Cucullaea  cf.  mathewsonii  Gabb  

X         

.... 

.... 

Corbula,  sp.,  a  

X 

x 

.... 

Crassatellites  grandis  (Gabb)  

X 

X?         ....           X         ....           X 

X 

.... 

Crassatellites  claytonensis,  n.  sp.  

X 

X 

.... 

Crassatellites  unioides  (Stanton)  

X           X 

x      x 

x 

Crassatellites  stewartvillensis,  n.  sp... 

X 

x 

.... 

Crassatellites    sp     a 

x 

Crassatellites  studleyi,  n.  sp  

X 

X 

.... 

.... 

Dosinia(^)  lawsoni    n  sp 

x 

x 

x 

Glycimeris  veatchii,  var.  major  Stanton 

X           X 

X         X 

X 

X? 

Glycimeris  cf.  veatchii  var.  major 

Stanton 

x 

x 

Leda  gabbi  Conrad  

X          X 

X        ....           XXX 

x 

.... 

Leda  alaeformis  (Gabb)   

X           X 

X        X 

X 

Leda  packardi,  n.  sp  

X           X 

X        X 

X 

.... 

Leda  cf    packardi    n  sp 

x 

Leda  milleri,  n.  sp  

X 

X 

.... 

Lima  multiradiata  Gabb  

X 

X         X 

X 

.... 

Lima  cf.  multiradiata  Gabb  

X 

X? 

.... 

Lima(?)   haseltinei,  n.  sp  

X 

X 

.... 

Lima(?)  claytonensis,  n.  sp  

X 

x 

.... 

Meretrix  stantoni,  n.  sp  

X 

X         X? 

X 

.... 

Meretrix  dalli,  n.  sp  

X 

X        

X 

Meretrix  cf.  stantoni,  n.  sp  

X 

x 

.... 

Meretrix,  sp.,  a  

X 

x 

x 

.... 

Meretrix,  sp.,  &  .. 

x      

Mactra(?)  tenuissima  Gabb  

X 

X        X 

X 

Modiolus  ornatus  (Gabb)   

X           X 

X         ....           XXX 

X 

.... 

Modiolus  merriami  (Weaver)  

X 

XXX 

.... 

.... 

Modiolus  bakeri,  n.  sp  

X           X 

x 

x 

.... 

Modiolus,  sp.  indet. 

x 

Modiolus,  sp.  indet  ... 

X 

108  University  of  California  Publications  in  Geology          [VOL.  8 

LIST  OF  MARTINEZ  SPECIES — (Continued) 

MARTINEZ  LOCALITIES  RANGE  OF  SPECIES 


°l 

Si         |          o 

to 
J3 
i           "S  ® 

SO 

8"    -a   1 

•^   rt             O   O              ^    CH 

.—   £3 

"^  °           v          PH-^           C 

rH     N               J3  •  —                  **•*     N                     O 

£  p 

g.~     §3     £s      .« 

?»»  W             0             03  0             9> 

E-ipQ          H         GOPn         EH 

•3  g         gg          w-3          J3 

Martesia(f),  sp  

X         

X 

Macrocallista(?)  packi,  n.  sp  

X           X 

x 

Mytilus  cf  ascia  Gabb                                   x 

Neaera  dolabraeformis  Gabb  x 

X         X? 

X           X 

Neaera  hannibali,  n.  sp  

X         

x      

Nucula  (Acila)  truncata  Gabb  

x      

X           X         ....            X 

Nucula  (Acila),  sp  x 

x 

Ostrea,  sp  x 

x 

Ostrea  weaveri,  n.  sp  

X            X         

x?      

Ostrea  buwaldana,  n.  sp  

X           X 

x 

Ostrea  appressa  Gabb  

x      

Paphia(?)  clarki,  n.  sp  x 

x      

X 

Paphia,  sp.,  a                                                x 

Pecten,  sp  

X         

Pecten  interradiatus  Gabb  

X         X 

X 

Pecten,  sp.         .                                               x 

Perna,  sp  

x      

Pholadomya  nasuta  Gabb  x 

X           X         

XXX 

Pinna  barrowsi,  n.  sp  

X         

x      

Phacoides  muirensis,  n.  sp  

X         

X          

Phacoides  quadrata,  n.  sp  

x      

x 

Phacoides  diaboli,  n.  sp.* 

Phacoides,  sp  

x 

Phacoides  turneri  (Stanton)  x 

X            X         

X            X 

Phacoides,  sp  x 

X          



Plicatula  ostreaf  ormis  Stanton       

X         .    . 

Psammobia(?)  cylindrica,  n.  sp  

X           X         

x      

Psammobia  hornii  (Gabb)   

X            X         ....            X 

XXX 

Solen  parallelus  Gabb(?)  

X         ....            X 

Solen,  sp  x 

X            X         

Solen  stantoni  Weaver  x 

x      x 

X         ....            X 

Spisula(?)  weaveri,  n.  sp.  Packard....       x 

X 

Tapes(?)  quadrata  Gabb  x 

X         ....            X            X 

X           X 

Tapes  cf.  quadrata  Gabb  

x      

Tellina(?)  undulifera  Gabb  x 

X           X         

XXX 

Tellina  kewi,  n.  sp  

X            X         

X           X 

Tellina  packardi,  n.  sp  

X         

X 

Tellina  herndonensis,  n.  sp  

X        

X 

Tellina  cf.  parilis  Gabb  

x      

X 

Tellina    sp     a 

x 

Tellina    sp     b                                                   x 

Tellina  aequalis  Gabb  x 

X            X          ....         X? 

X           X 

Tellina  perrini,  n.  sp  

X         

X 

Teredo,  sp  x 

X         ....            X 

X           X 

1914]       Dickerson :  Fauna  of  the  Martinez  Eocene  of  California        109 
LIST  OP  MARTINEZ  SPECIES — (Continued} 


MARTINEZ  LOCALITIES                 RANGE  OF  SPECIES 

•So 

*t 

~r 

> 

|S 

13  * 

"~!  °          a3 

I     ll  11 

*a      §      g*     -S- 

!•-    § 

Is 

31         3 

i'o        *5?      "3  '3       °:§ 

a)-3         !3 
S-3         0 

Venus(?),  sp  

X 

Venericardia  planicosta  Lamarck  

X 

....         X?         ....         X? 

X 

Yoldia(?)  powersi,  n.  sp  x 

X 

Yoldia  gesteri,  n.  sp  

X 

X 

Zirphaea(f),  sp  x 

X 

Dentalium  cooperi  Gabb  x 

X            X 

X            X            X            X 

X           X 

Dentalium  stramineum  Gabb  x 

X            X 

XXX 

X            X 

Acmaea  martinezensis,  n.  sp  

X 

X 

Alaria,  sp  

X 

Ampullina  cf.  striata  Gabb  

X 

x 

.... 

Ampullina  striata  Gabb  x 

X 

X 

Amauropsis(?),  sp  

X 

Amauropsis  martinezensis,  n.  sp  x 

X           X 

x 

X 

Anchura  englishi,  n.  sp  

X 

X 



Anchura,  sp  x 

X 

Anchura  gabbi,  n.  sp  x 

X 

Architectonica  tuberculata  Weaver  

X 

....  -    ....        x 



Architectonica    sp. 

x 

Actaeon  lawsoni  Weaver  

X 

x 



Bullinula  subglobosa  \Veaver 

x 

x 

Brachysphingus  liratus  Gabb  x 

X            X 

X?            X            X 

X 

Brachysphingus  sinuatus  Gabb 

x 

Chlorostoma(  ?),  sp. 

x                   

Cylichna  costata  Gabb  x 

X            X 

X            X            X            X 

X           X 

Cassidaria  tuberculata  (Gabb)  

X?          .... 

X         ....         X? 

Cerithiopsis  alternata  Gabb  

X 

x      

X 

Cypraea  bayerquei  Gabb  

X 

X 

X 

Cerithium,  sp.                     .             

X 

x 

Discohelix   sp    tt                                            x 

x 

Discohelix  californicus  Weaver  

X 

X 



Ficopsis,  sp  x 

X 

X 

X 

Fissurella(?)  behri,  n.  sp  

X 

X 

Fusus  aequilateralis  Weaver  

X 

X           X 



Fusus(?),  sp.,  a  

X 

X 



Fusus  occidentalis  Gabb  

X 

X 

.... 

Fusus  flexuosus  Gabb 

X 

X 



Fusus  cf.  mathewsonii  Gabb  

X 

X 

Fusus  mathewsonii  Gabb  x 

X 

XXX 

X 

Fusus  aratus  Gabb  

X 

X 

Fusus  martinez  Gabb  

X 

X         ....           X 

Fusus(?),  sp.,  &  x 

X 

Fusus  dumblei,  n.  sp  

X 

X 

Fusus  cf.  martinez  x 

X 

Fusus,  sp.,  d  x 

X 

110  University  of  California  Publications  in  Geology          [VOL.  8 

LIST  OF  MARTINEZ  SPECIES — (Continued) 

MARTINEZ  LOCALITIES  RANGE  OF  SPECIES 


Fususf?}    sp. 

Martinez  N.  of  *\ 
^  Mount  Diablo 

Type  locality, 
Benicia,  Selby 

3 

!  L    Is  I! 

0              03  '3            '57          *o  9            2^ 
i-5           CCPk          E-<         02  .8         EH  '3 

Meretrix 
<  dalli  zone 

Chico 

Galerus  excentricus  Gabb  

X 

XXX                          X 

X 

Heteroterma  gabbi  Stanton  

X 

x      

Heteroterma  trochoidea  Gabb 

X 

x 

x 

Heteroterma  striata  Stanton 

X 

x                          x 

x 

Heteroterma,  sp.  indet  

X 

X         .—                                     X 

x 

Hemifusus(?)  waringi,  n.  sp  

X 

HipponyxC  ?),  sp. 

x 

Lunatia  hornii  Gabb     

x 

X 

X        ....           X                        X 

x 

Lunatia  cf.  nuciformis  Gabb  

X         ....            X 

x 

Lunatia,  sp.  a, 

x 

Megistostoma  striata  Gabb(?) 

X? 

X        X? 

Neptunea  mucronata  Gabb  

x 

X 

x 

X 

Neptunea  (Tritonofusus)  cretacea, 
Gabb 

x 

x 

Neptunea,  sp.,  a  

X 

Natica  (Gyrodes)  lineata,  n.  sp  

x 

X         X 

Natica,  sp.,  a 

x 

x 

Natica,  sp.,  &      .... 

x      

Natica,  sp.,  c 

x 

Natica,  sp.,  e 

x 

Naticina,  sp. 

x 

x 

Nerita  biangulata,  n.  sp. 

x 

X 

Niso  polito  Gabb  

x 

X         

X 

Ovula  martini,  n.  sp. 

x 

x 

x 

X 

Olivella  claytonensis,  n.  sp. 

x 

x 

Perissolax  tricarnatus  Weaver  

x 

x 

X         ....            XXX 

X 

Patella,  sp. 

x 

Patella    sp 

x 

Ringinella  pinguis  Gabb  

x 

x 

X          X 

X 

Surcula  merriami,  n.  sp. 

x 

X 

Surcula  (Surculites)  inconspicua  Gabb 

x 

x 

Surcula  fairbanksi  n  sp 

x 

x 

Surcula  (Surculites)   andersoni,  n.  sp. 
Surcula   sp 

x 

x 

X 



Siphonalia(?)  lineata  Stanton  

x 

x 

x      x        x 

X 

Strepsidura  pachecoensis  Stanton 

x 

x 

Spirocrl  vphus  (  ?  )    SP 

x 

Seraphs  (?)  thompsoni,  n  sp 

x         .        ..       

X 

Turbinella  crassatesta  Gabb 

x 

x 

Turritella  martinezensis  Gabb 

x 

X                                                    X 

Turritella  cf   martinezensis  Gabb 

x 

Turritella  pachecoensis  Stanton  
Turritella  cf.  pachecoensis  Stanton  ... 

X 

X 

x      x 

X 

X 

1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        111 

LIST  OF  MARTINEZ  SPECIES — (Continued') 

MARTINEZ  LOCALITIES  RANGE  OF  SPECIES 


^3      £|       « 

^i  c3        ^3  QO         ^          o                         A             ta^ 

I5    §-•    *    i          is    SI    .«§ 

3  8      "^2        ®       ^  •*•        «       <a  §      ^  —       •£>  N        o 

h  &         Q/3          i          ac          o         E~<         «"»         2s          ° 

M^       Rj        o        1?       '5?     "3  g       2S      .s-s       S 

S^        HPQ         hJ         CQPn         EH        022        EH'N        S'O         O 

Turritella  infragranulata  Gabb  ... 

XXX         ....         ....           XXX 

Turritella  conica  Weaver  

x      x?      x?      

Turritella  clarki,  n.  sp. 

x                                                     x 

Turris,  sp.,  a 

x 

Turris  claytonensis  Gabb*  

X         .   . 

Turris    sp    indet 

x 

Tritonium  martinezensis,  n.  sp.  ... 

X         X         X 

Tritonium,  sp.,  a 

x         

Tritonium  buwaldi,  n.  sp  

X         X 

Tritonium(?),  sp  

X                                                               X 

Tritonium  pulchrum  Weaver 

x               .  .                 x                  

Tritonium,  sp  

x 

Urosyca  caudata  Gabb  

XXX         XXX 

Urosyca  robusta  Weaver  

X           X         X           X 

Xenophora  zitteli  Weaver  

X           X         X           X 

Aturia  mathewsonii  Gabb* 

x                            

Hercoglossa  merriami,  n.  sp  

X        X        

Nautilus  stephensoni,  n.  sp  

X         X        

Crustacean  remains 

x                                    

Shark   tooth   

X           X         X           X 

Leaf 

X                                                                                                        —  • 

Fossil  wood 

*  South  of  Mount   Diablo. 

SUGGESTION  OF  FAUNA  AS  TO  CLIMATE  DURING  MARTINEZ  TIME 

The  collections  from  strata  of  Martinez  age  contain  the  genera 
Cypraea,  Ovula,  Aturia,  Turris,  and  Surcula,  which  are  represented 
mainly  by  tropical  or  subtropical  species  in  the  ocean  of  the  present 
time.  Several  genera  which  are  now  represented  by  boreal  or  tem- 
perate species  are  found  in  this  fauna  as  well.  This  evidence  seems 
to  indicate  that  the  climate  of  Martinez  time  was  decidedly  milder 
than  that  of  the  Recent  period  in  these  latitudes.  The  mixture  of 
subtropical  and  boreal  forms  indicates  a  warm  temperate  climate. 
Practically  none  of  the  genera  mentioned  above -occur  in  the  Chico, 
and  an  absence  of  other  tropical  or  subtropical  genera  from  the 
uppermost  Cretaceous  shows  some  change  in  climate  between  Chico 
and  Martinez  times.  Tejon  climate,  however,  was  decidedly  warmer 


112  University  of  California  Publications  in  Geology          [VOL.  8 

than  that  of  the  Martinez,  judging  from  the  much  greater  abundance 
of  tropical  forms  represented  in  its  fauna.  For  a  discussion  of  the 
Tejon  climate  the  reader  is  referred  to  a  recent  paper  by  the  writer27 
on  the  Eocene  of  the  Marysville  Buttes. 


RELATIONSHIP  OF  THE  CHICO  AND  MARTINEZ  FAUNAS 

The  check-list  given  above  shows  that  the  following  Chico  species 
range  upward  into  the  Martinez:  Nucula  truncata  Gabb,  Cylichna 
costata  Gabb,  Dentalium  cooperi  Gabb,  Dentalium  stramineum  Gabb. 
All  of  these  species  appear  practically  identical  with  those  of  the 
Chico,  but  unfortunately  they  represent  genera  whose  species  are 
usually  very  persistent.  Tellina  cf .  parilis  Gabb  which  was  found  near 
Lower  Lake  is  nearly  identical,  as  far  as  external  form  is  concerned, 
with  T.  parilis  of  the  Chico.  Meretrix(f)  dalli,  n.  sp.,  is  very  similar 
to  M.  fragilis  Gabb  of  the  Chico.  Glycimeris  veatchii  var.  major 
(Stanton)  is  distinguishable  from  G.  veatchi  (Gabb)  but  it  is  evidently 
a  descendant  of  the  Chico  form.  Amauropsis  martinezensis,  n.  sp.,  is 
allied  to  A.  oviformis  Gabb  in  the  strata  beneath.  The  Cretaceous 
genera  Ringinella  and  Anchura,  are  represented  by  E.  pinguis  Gabb, 
A.  englishi  and  A.  gabbi,  n.  sp.,  respectively. 

This  evidence  indicates  a  much  closer  relationship  between  the 
Eocene  and  the  Cretaceous  than  is  generally  found. 


FAUNAL  RELATIONSHIP  OF  THE  MARTINEZ  TO  THE  TEJON 

The  relationship  between  the  Tejon  and  the  Martinez  is  shown  by 
the  list  given  above.  About  twenty-five  to  thirty  species  range  through 
portions  of  both  groups.  About  fifteen  to  twenty  of  these  range  from 
the  base  of  the  Martinez  to  at  least  as  high  as  the  middle  Tejon  of 
the  Mount  Diablo  region,  and  some  of  these  extend  even  to  uppermost 
Eocene  at  the  Marysville  Buttes.  The  following  are  species  common 
to  both  the  Martinez  and  the  Tejon: 

Schizaster  lecontei  Merriam  Leda  gabbi  Conrad 

Cardium  cooperi  Gabb  Modiolus  merriami  (Weaver) 

Crassatellites  grandis  (Gabb)  Modiolus  ornatus  (Gabb) 

*Cuspidaria  dolabraef ormis  (Gabb)(?)  Nucula  (Acila)  cf.  truncata  Gabb 

*  Described  by  Gabb  from  his  Cretaceous  B  (=  Tejon). 


27  Dickerson,  Koy  E.,  Fauna  of  the  Eocene  at  Marysville  Buttes,  California, 
Univ.  Calif.  Publ.  Bull.  Dept.  Geol.,  vol.  7,  p.  267,  1913. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        113 


fOstrea  appressa  Gabb(?) 
Pecten  interradiatus  Gabb 
Psammobia  hornii  (Gabb) 

fSolen  parallelus  Gabb 
Tapes (?)quadrata  (Gabb) 

tVenericardia  planicosta  Lamarck  (  ?) 
Cylichna  costata  Gabb 
Cerithiopsis  alternata  Gabb 

*Cuspidaria  dolbraformis  (Gabb)  (?) 


Dentalium  cooperi  Gabb 
Dentalium  stramineum  Gabb 
Fusus  martinez  Gabb 
Fusus  mathewsonii  G&bk 
Galerus  excentricus  Gabb 
Lunatia  hornii  Gabb 
Niso  polito  Gabb 
Perissolax  tricarnatus  Weaver 
Aturia  mathewsonii  Gabb 


*  Described  by  Gabb  from  his  Cretaceous  B  (=  Tejon). 
t  Keported  by  Stanton  from  Lower  Lake. 


Perissolax  tricarnatus  and  Schizaster  lecontei  occur  abundantly  in 
the  type  section  of  the  Tejon  near  Fort  Tejon.  Modiolus  merriami 
was  found  in  the  Tejon  on  the  south  side  of  Pine  Canon,  Mount 
Diablo  Quadrangle,  by  the  Summer  Session  class  in  palaeontology. 
Flabellum  remondianum  is  questionably  reported  from  the  Tejon. 
The  following  species  were  indeterminate :  Avicula  cf .  pellucida  Gabb, 
Megistostoma  striata  Gabb  ( ? ) . 

The  type  specimen  of  Turritella  conica  Weaver  appears  very 
similar  to  a  Turritella  in  the  Tejon,  but  owing  to  the  poor  preservation 
of  the  type  it  is  impossible  to  decide  the  point.  Cassidaria  tuber- 
culata  (Gabb)  is  questionably  reported  from  the  Martinez  at  Benicia. 

The  absence  of  the  common  Martinez  species,  such  as  Trochocyathus 
zitteli  (Merriam),  Cardita  veneriformis  Gabb,  Cucullaea  mathewsonii 
Gabb,  Crassatellites  unioides  Stanton,  Glycimeris  veatchii,  var.  major 
(Stanton),  Lucina  turneri  Stanton,  Leda  alaeformis  (Gabb),  Meretrix 
stantoni,  n.  sp.,  Pholadomya  nasuta  Gabb,  Tellina  undulifera  Gabb, 
Ampullina  striata  Gabb,  Amauropsis  martinezensis,  n.  sp.,  Discohelix 
calif ornicus  Weaver,  Heteroterma  gabbi  Stanton,  Heteroterma  striata 
Stanton,  Natica  lineata,  n.  sp.,  Ringinella  pinguis  Gabb,  Siphonalia(f) 
lineata  Stanton,  Turritella  martinezensis  Gabb,  Turritella  pachecoensis 
Gabb,  Turritella  infragranulata  Gabb,  and  Urosyca  caudata  Gabb 
from  an  Eocene  fauna  is  quite  sufficient  to  make  its  Martinez  age 
questionable.  These  species  are  excellent  guide  fossils  because  nearly 
any  fossiliferous  Martinez  locality  will  yield  at  least  three  or  four 
of  them.  Their  range  in  many  cases  is  through  the  entire  Martinez, 
but  so  far  as  known  none  occurs  in  the  Tejon  or  the  Chico.  A  study 
of  the  list  of  Martinez  species  shows  the  absence  of  a  great  many 
typically  Tejon  species.  Among  the  absent  ones  are :  Cardium  breweri 
Gabb,  Cardita  planicosta  var.  hornii  (Gabb),  Corbula  parilis  Gabb, 


114 


University  of  California  Publications  in  Geology          [VOL.  8 


Dosinia  elevata  Gabb,  Dosinia  gyrata  Gabb,  Glycimeris  sagittata  Gabb, 
Meretrix  hornii  Gabb,  Meretrix  ovalis  Gabb,  Meretrix  uvasana  Gabb, 
Ostrea  aviculaformis  Anderson,  Placunanomia  inornata  Gabb,  Tapes 
conradiana  Gabb,  Tellina  longa  Gabb,  Tellina  remondii  Gabb,  Amau- 
ropsis  alveata  Gabb,  Bulla  hornii  Gabb,  Fusus  californica  Gabb, 
Rimella  canalifera  Gabb,  Turritella  merriami  Dickerson,  Turritella 
uvasana  Conrad,  Whitneya  ficus  Gabb.  Many  of  these  forms  have  a 
wide  range  in  the  Tejon,  but  so  far  as  known  they  are  not  fo.und  in 
the  Martinez.  There  are  many  other  Tejon  forms  which  will  serve  as 
guides.  The  faunal  break  between  the  Martinez  and  the  Tejon  is 
very  wide  when  we  consider  the  large  number  of  species  which  are 
confined  to  the  one  group  or  the  other. 

i 

COMPARISON  OF  THE  UPPEE  MARTINEZ   AND   THE 
LOWERMOST  TEJON 

During  the  last  two  Summer  Sessions  of  the  University  the  field 
classes  in  palaeontology  made  extensive  collections  in  the  Tejon,  south 
of  Mount  Diablo.  As  was  mentioned  above  in  describing  the  small 
area  of  Martinez  south  of  Mount  Diablo,  the  Tejon  for  the  most  part 
is  in  unconformable  contact  with  the  Chico.  Between  Cave  Point  and 
Oyster  Point  a  complete  section  of  the  Tejon  was  studied  and  it  was 
found  to  be  fossiliferous  from  top  to  botton.  The  basal  portion  in 
contact  with  the  Chico  was  most  prolific  and  yielded  a  very  large 
fauna,  a  portion  of  which  is  given  in  the  list  below.  This  basal  fauna 
was  obtained  from  beds  not  over  twenty-five  feet  above  the  bottom  of 
the  section. 


PARTIAL  LIST  OF  SPECIES  IN  THE  BASAL  TEJON  SOUTH  OF  MOUNT  DIABLO 


Fungia(f),  n.  sp. 
Turbinolia(f),  n.  sp.,  a  (long) 
Turbinolia(?),  n.  sp.,  b   (short) 
Coral  (reef  form),  sp. 
Cassidulus  californicus  Anderson 
Scutella,  n.  sp. 
Acila,  sp. 

Astarte  mathewsonii  Gabb 
Avicula  pellucida  Gabb 
Cardium  cooperi  Gabb 
Cardium,  sp. 
Corbula  parilis  Gabb 
Dosinia  elevata  Gabb 
Dosinia  gyrata  Gabb 


Glycimeris  cf.  sagittata   (Gabb) 
Glycermis  cor  (Gabb) 
Leda  gabbi  Conrad 
Mactra,  sp. 
Spisula,  n.  sp. 
Meretrix  hornii  Gabb 
Meretrix  ovalis  Gabb 
Meretrix  uvasana  Gabb 
Modiolus  ornatus  (Gabb) 
Ostrea  aviculaformis  Anderson 
Ostrea,  sp. 
Phacoides,  sp. 

Placunanomia  inornata  Gabb 
Psammobia  hornii  (Gabb) 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        115 

PARTIAL  LIST  OF  SPECIES  IN  THE  BASAL  TEJON  SOUTH  or  MOUNT  DIABLO — 

(Continued) 

PteriaC?),  sp.  Cassidaria  tuberculata  (Gabb) 

Solen  parallelus  Gabb  Ficopsis  remondii  (Gabb) 

Tapes  conradiana  Gabb  Fusus  californica  Gabb 

Tapes,  sp.  Fusus  diaboli  Gabb 

Tapes(f)  quadrata  Gabb  Fusus  martinez  (Gabb) 

Tellina  cf.  aequalis(?)  Gabb  Fusus,  sp. 

Tellina  longa  Gabb  Galerus  excentricus  Gabb 

Tellina  remondii  Gabb  Littorina  compacta?  Gabb 

Tellina,  n.  sp.  Lunatia  hornii  Gabb 

Venus (?),  sp.,  a  Neptunea(?)  supraplicata  Gabb 

Venus (?),  sp.,  ~b  Neptunea(?),  sp. 

Venericardia  planicosta  Lamarck,  Neverita  secta  Gabb 

var.  hornii  Gabb  Olivella  mathewsonii  Gabb 

Yoldia(?),  n.  sp.  Perissolax  blakei  Gabb 

Zirphaea(?),  sp.  Pseudoliva  volutaeformis  Gabb 

Eimella  canalifera  Gabb 

Dentalium  cooperi  Gabb  Surculites,  sp. 

Dentalium  stramineum  Gabb  Turris  perkinsiana  (Cooper) 

Amauropsis  alveata  Gabb  Turris,  sp.,  a 

Bulla  hornii  Gabb  Turris,  sp.,  & 

Cylichna  costata  Gabb  Turritella  merriami  Dickerson 

The  basal  Tejon  in  contact  with  the  upper  Martinez  of  the  type 
section  is  non-fossiliferous  and  on  this  account  a  direct  comparison 
with  the  upper  Martinez  is  not  possible.  The  Tejon  south  of  Mount 
Diablo  is  only  ten  miles  away  from  the  upper  Martinez  of  the  type 
section,  so  a  comparison  between  the  two  is  profitable. 

The  following  species  are  common  to  the  two : 

Cardium  cooperi  Gabb  Dentalium  cooperi  Gabb 

Leda  gabbi  (Conrad)  Dentalium  stramineum  Gabb 

Modiolus  ornatus  (Gabb)  Lunatia  hornii  (Gabb) 

Acila,  sp.  Perissolax  tricarnatus(?)  Gabb 
Psammobia  hornii  (Gabb) 

Such  characteristic  species  as  the  following  are  not  found  in  the 
basal  Tejon : 

Cucullaea  mathewsonii  Gabb  Fusus  aequilateralis  Weaver 

Pholadomya  nasuta  Gabb  Heteroterma  gabbi  Stanton 

Tellina  kewi,  n.  sp.  Heteroterma  trochoidea  Gabb 

Tellina  undulifera  Gabb  Siphonalia(f)   lineata  Stanton 

Ampullina  striata  Gabb  Turritella  pachecoensis  Stanton 

Brachysphingus  liratus  Gabb  Urosyca  caudata  Gabb 
Bullinula  subglobosa  Weaver 

This  faunal  difference  would  be  far  better  shown,  no  doubt,  if 
better  collecting  places  in  the  uppermost  Martinez  could  be  found. 


116  University  of  California  Publications  in  Geology          [VOL.  8 

In  making  our  comparisons  between  faunas,  the  condition  of 
deposition  should  be  stated.  The  fauna  of  the  uppermost  Martinez 
flourished  in  moderately  deep  water  while  that  of  the  basal  Tejon  is 
littoral.  Luckily  we  do  have  a  moderately  deep-water  fauna  contained 
in  the  Tejon  beds  just  overlying  the  basal  beds.  These  beds  south 
of  Mount  Diablo  are  about  fift}^  to  seventy-five  feet  thick  and  they 
have  yielded  Schizaster  lecontei,  Pecten  interradiatus  and  several 
species  of  foraminifers.  They  are  in  turn  succeeded  by  Turritella 
uvasana  beds  which  yield  a  typical  Tejon  fauna  of  the  inshore  type. 
These  last  mentioned  horizons  are  represented  at  the  type  section  of 
the  Martinez  by  fossiliferous  beds.  The  Turritella  uvasana  beds  near 
Muir  Station  contain  a  typical  Tejon  fauna,  but  the  shales  and 
glauconitic  sands  beneath  have  yielded  a  fauna  which  was  so  unusual 
for  the  Tejon  that  Dr.  "Weaver  included  it  in  the  Martinez.  This 
fauna  is  as  follows : 

Loc.          Loc.          Loc. 
215  337  532 

Nummuloid(?),  sp x 

Orbitoides,   sp x 

Cardium  cooperi  Gabb x  x 

Cassidaria  tuberculata  (Gabb)  x 

Modiolus  merriami  (Weaver)  x 

Leda  gabbi  Conrad x 

Tellina  hornii  Gabb  x 

Tellina  cf.  remondii  Gabb  x 

Tellina  martinezeusis  Weaver  *  x 

Thracia  karquinezensis  Weaver  x             x 

Solen  parallelus  Gabb  

Solen  stantoni  Weaver  x  ....             x 

Venericardia  planicosta  Lamarck x 

Bela  cf.  clathrata  Gabb  x 

Ficopsis  remondii  Gabb  x 

Megistostoma  striata  Gabb  

Perissolax,  n.  sp  ....             x 

Eimella  canalifera  Gabb x 

SpiroglyphusC?)  tejonensis  Arnold  

Turris  monolifera  Cooper  x 

Turritella  conica  Weaver  x 

Tritonium  eocenicum  Weaver  x 

Tritonium  impressum  Weaver  x 

Of  these  forms  Solen  parallelus,  Venericardia  planicosta,  Bela 
clathrata,  Ficopsis  remondii,  Cassidaria  tuberculata,  Rimella  canali- 
fera, Spiroglyphus(f)  tejonensis,  Turris  monolifera  are  typical  of  the 
Tejon.  No  typical  Martinez  species  such  as  Tellina  undulifera, 
Cucullaea  mathewsonii,  Urosyca  caudata  or  Brachysphingus  liratus 
have  been  found  in  these  strata. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        117 

TIME-INTERVAL  BETWEEN  DEPOSITION  OF  MARTINEZ  AND  TEJON 

The  time-interval  which  elapsed  between  the  deposition  of  these 
gray-green  Tejon  shales  and  the  uppermost  Martinez  strata~rrrast  have 
been  very  great.  During  this  time  many  characteristic  Martinez 
species  entirely  disappeared.  A  portion  of  this  time-interval  is  prob- 
ably represented  by  unconformity  between  the  lowermost  Tejon  strata 
and  the  Martinez,  although  there  is  no  one  place  yet  discovered  at  the 
type  locality  which  proves  this  fact.  A  marked  change  in  lithology, 
a  considerable  difference  in  dip  throughout  the  field,  and  a  very 
abrupt  change  in  fauna  suggest  unconformity  at  the  type  locality. 


CORRELATION  OF  MARTINEZ  WITH  EOCENE  OF  THE 
ATLANTIC  AND  GULF  STATES 

Dr.  W.  H.  Dall29  first  attempted  a  correlation  of  the  Pacific  Coast 
Eocene  with  that  of  the  eastern  states.  In  this  general  correlation 
paper,  the  Martinez  and  Tejon  were  correlated  with  the  lower  portion 
of  the  Eocene.  Weaver,30  in  his  paper  on  the  palaeontology  of  the 
Martinez  Group,  correlates  the  Martinez  with  the  Midway  of  the  Gulf 
States  region.  He  says : 

"For  comparison  with  the  Martinez  fauna,  the  following  important  locali- 
ties have  been  selected:  the  Gulf  States,  the  Atlantic  States,  the  London  and 
Paris  Basins,  and  the  Sind  district  of  western  India. 

"Compared  with  these  the  fauna  of  the  Martinez  Group  seemed  to  be  a 
distinct  unit.  Of  the  forty-nine  genera  listed  only  twenty-two  could  be  found 
in  the  literature  on  the  Eocene  of  the  Gulf  and  Atlantic  States.  No  species 
were  found  in  common  yet  several  were  somewhat  similar.  This  fauna  has  its 
closest  affinities  with  that  represented  in  the  Midway  of  the  Gulf  States  and 
the  Aquia  stage  of  Maryland  and  Virginia.  The  correspondence  to  the  Aquia 
is  however  less  marked  than  to  the  Midway.  .  .  .  The  fauna  of  the  Tejon 
Group  bears  a  closer  similarity  to  both  the  Aquia  and  Chickasawan  than  does 
the  Martinez." 

Weaver  also  concludes  from  a  comparison  with  the  London  Basin 
and  Paris  Basin  faunas  that  the  Martinez  is  more  nearly  related  to 
the  fauna  of  the  Thanet  Sands  and  the  Bracheux  Beds.  He  states: 
' '  the  Martinez  may  represent  some  portion  or  all  of  the  lower  quarter 
of  the  Eocene." 


29  Ball,  W.  H.,  18th  Ann.  Eept.  U.  S.  Geol.  Surv.,  pt.  2,  pp.  327-328,  1898. 
so  Op.  cit.,  pp.  111-113. 


118  University  of  California  Publications  in  Geology          [VOL.  8 

The  writer  agrees  with  Dr.  Weaver's  position  in  correlating  the 
Martinez  with  the  Midway  of  the  Gulf  States.  The  Tejon  bears  a 
much  stronger  resemblance  to  the  Aquia  and  Chickasawan  than  does 
the  Martinez.  Harris31  has  given  an  excellent  summary  of  the  Midway 
stage. 


GENERA  COMMON  TO  MARTINEZ  AND  MIDWAY 

There  are  several  species  figured  by  Harris  which  are  very  close 
to  forms  found  in  the  Martinez-  Ostrea  crenulimarginata  Gabb 
resembles  Ostrea  buwaldana  very  closely,  if  it  is  not  identical  with  it. 
Modiolus  saffordi  (Gabb)  resembles  Modiolus  ornatus  (Gabb).  Cucul- 
laea  saffordi  Gabb  resembles  Cucullaea  mathewsonii  Gabb.  The 
variety  Venericardia  planicosta  called  Venericardia  alticostata  Conrad 
resembles  a  species  found  in  the  uppermost  Martinez,  but  none  of  the 
species  of  Venericardia  figured  by  Harris  vary  from  the  type  of  V. 
planicosta  as  much  as  does  Cardita  veneriformis  Gabb. 

Fulgur(f)  dallianum  Harris  looks  like  Perissolax  blakei.  Gyrodes 
alabamensis  Whitf.  resembles  Gyrodes  lineata,  n.  sp.,  of  the  Martinez. 
Hercoglossa  (Enclimatoceras)  ulrichi  White  bears  a  very  close 
resemblance  to  Hercoglossa  merriami,  n.  sp.  Thus  we  see  that  even 
some  specific  resemblances  can  be  found  between  the  faunas  of  the 
lower  Eocene  of  the  east  coast  and  the  Martinez  of  the  west. 

The  following  genera  are  common  to  the  Martinez  and  the  Midway : 

Ostrea  Tellina 

Plicatula  Corbula 

Pecten  Lucina 

Avicula  Martesia 

Perna  Pholadomya 

Modiolus  Dentalium 

Area  Actaeon 

Cucullaea  Cyliehna 

Glycimeris  Turris 

Nucula  Pseudoliva 

Leda  Surcula 

Yoldia  Olivella 

Venericardia  Fusus 

Astarte  Triton  (=Tritonium) 

Crassatellites  Strepsidura 

Protocardia  Neptunea 

Meretrix  Cypraea 


si  Harris,  G.  D.,  The  Midway  Stage,  Bull.  no.   4,  American  Palaeontology, 
pp.  1-156,  June,  1896. 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        119 

Cerithium  Natica 

Turritella  Gyrodes 

Architectonica  Amaura  (=  Amauropsis) 

Calyptraea  Fissurella 

Xenophora  Enclimatoceras   (=  Hercoglossa) 

Pyrula  is  the  equivalent  of  Ficopsis.  Fulgur(f)  dallianum  Harris 
is  rather  close  to  Perissolax  blakei  Conrad.  They  are  generically  the 
same,  at  least. 

GENERA  PRESENT  IN  MIDWAY  BUT  ABSENT  IN  MARTINEZ 
The  following  genera  listed  by  Harris  have  not  been  found  in  the 
Martinez : 

Lithodomus  Pyropsis 

Chama  Leucozonia 

Gastrochaena  Mazzalina 

Verticordia  Levifusus 

Cadulus  Levibucinum 

Atys  .  Murex 

Pleurotomella  Calyptraphorus 

Drillia  Aporrhais 

Caricella  Mesalia 

Scaphella  Eissoina 

Voluta  Keilostoma 

Lyria  Scala 

Mitra  Solariella 

Exilia  Pleurotomaria 

Of  these  missing  genera  the  following  are  found  in  the  Tejon,  the 
upper  Eocene  of  the  west  coast:  Cadulus  (represented  by  Dentalium 
pusillum  Gabb),  Drillia,  Caricella,  Voluta,  Mitra,  Exilia  (represented 
by  Fusus  dicker  soni  Weaver)  Lyria,  n.  sp. 

PROPOSED  CORRELATION 

The  absence  of  several  of  the  genera  mentioned  from  the  Martinez 
such  as  Drillia,  Caricella,  Voluta,  Mitra,  Exilia,  and  Pseudoliva  which 
are  typical  Eocene  forms  over  the  world  suggests  that  the  Martinez 
represents  a  stage  in  the  Eocene  of  the  United  States  which  is  at  least 
in  part  decidedly  lower  than  the  Midway. 

On  account  of  the  close  relationship  of  the  Martinez  to  the  Chico- 
Cretaceous,  the  much  greater  thickness  of  the  Eocene  strata  on  this 
coast  compared  to  that  of  the  Gulf  States,  and  the  absence  of  certain 
genera  typical  of  upper,  middle  and  lower  Eocene,  the  writer  con- 
cludes that  the  Martinez  is  not  only  equivalent  to  a  portion  of  the 
Midway,  but  represents  a  still  earlier  stage  of  the  Eocene  as  well. 


120  University  of  California  Publications  in  Geology          [^OL.  S 

SUMMARY 

Conclusions  based  upon  the  work  of  all  investigators  are  as  follows : 

1.  The  Martinez  Group  is  a  definite  unit  both  stratigraphically 
and  faunally. 

2.  An  unconformity  exists  between  the  Martinez  and  the  under- 
lying Chico  and  between  the  Martinez  and  the  overlying  Tejon. 

3.  The  Martinez  was  deposited  in  two  distinct  basins,  one  being  in 
the  vicinity  of  San  Francisco  Bay  and  the  other  in  the  neighborhood 
of  Los  Angeles. 

4.  These  basins  of  deposition  are  only  partially  coextensive  with 
the  larger  basin  of  the  Tejon. 

5.  The  faunal  differences  between  Chico  and  Martinez  and  between 
the  Martinez  and  the  Tejon  are  very  great. 

6.  Three  major  faunal  zones  have  been  recognized  in  the  Martinez 
Group. 

7.  The  Martinez  is  in  part  the  correlative  of  the  Midway  of  the 
Gulf  States  and  in  part  represents  a  division  of  time  earlier  than  the 
Midway. 

DESCRIPTIONS  OF  SPECIES 

ANTHOZOA 
FLABELLUM,  sp. 

A  short,  conical,  slightly  curved,  and  somewhat  compressed  form 
is  found  in  the  Martinez  at  San  Pedro  Point.  It  appears  to  have  about 
twenty-four  principal  septa  with  one  or  two  secondary  septa  in  the 
interspaces.  Costae  appear  to  correspond  to  each  of  the  principal 
septa.  The  principal  septa  appear  bifid  but  this  may  be  due  to 
weathering.  A  small,  short  pedicel  is  found  on  some  specimens. 

Dimensions. — Greater  transverse  diameter  of  calice,  9  mm. ;  lesser, 
8  mm. ;  height,  8.5  mm. 

Occurrence. — Martinez  at  San  Pedro  Point,  San  Mateo  County, 
California. 

PARACYATHUS(f),  sp. 

Plate  6,  figure  2 

Short,  conical,  circular,  with  base  truncated,  attached  at  truncation. 
Costae  correspond  to  all  the  principal  septa  which  are  numerous. 
About  thirty-six  of  these  were  counted.  One  and  sometimes  two 
secondary  septa  are  found  between  the  primary  ones.  Costae  appear 
to  be  granulated.  Wall  rather  thick. 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        121 

Dimensions. — Diameter  of  calice,  12  mm. ;  height,  9  mm. 
Occurrence. — Martinez  of  San  Pedro  Point,  San  Mateo  County, 
California. 

ECHINOIDEA 

CIDAKIS,  sp.,  a 

Plate  6,  figures  4a,  4& 

Test  unknown.  Spines  long,  very  slender,  circular  in  cross-section. 
Certain  incomplete  specimens  are  15  mm.  long  and  only  1  mm.  in 
diameter  with  only  a  slight  taper.  Surface  of  spine  marked  by  micro- 
scopic, longitudinal,  lines  or  ribs.  The  distal  end  is  marked  by  a 
small  ball  which  is  decorated  by  about  fourteen  strong  rounded  ribs. 
This  ball  terminates  in  a  rounded  tip.  The  base  is  marked  by  a  well- 
developed  collar  and  a  rounded  socket  in  its  end.  The  base  does  not 
appear  to  be  ornamented. 

The  surface  of  the  rock  is  covered  with  pieces  of  spines  which  have 
been  weathered  out.  The  description  is  based  upon  several  fragments 
of  spines. 

Occurrence. — University  of  California  Localities  245  and  1556, 
Martinez  Group. 

CIDARIS(?),  sp.,  c 
Plate  6,  figures  6a,  6b 

A  cast  of  a  hemispherical  test  with  the  mouth  and  apical  system, 
central  was  found  in  beds  of  Martinez  north  of  Mount  Diablo. 
Dimensions. — Height,  4  mm. ;  diameter,  6  mm. 
Occurrence. — University  of  California  Locality  1592,  two  and  one- 
half  miles  east  of  Clayton. 

SCHIZASTER    LECONTEI    Merriam 

Plate  6,  figure  7 
Schizaster  lecontei. — Merriam,  J.  C.,  Proceedings,  California  Academy  of 

Sciences,  Geology,  vol.  1,  pp.  164-165,  1899. 
California  Academy  of  Sciences,  vol.  1. 

1  i  Small  forms  averaging  a  little  less  than  20  mm.  in  length.  The  largest 
specimen  measured  is  about  23  mm.  long.  Test  distinctly  notched  anteriorly  by 
the  groove  of  the  anterior  ambulacrum  truncated  posteriorly;  upper  surface 
much  elevated,  with  a  sharp  ridge  running  from  the  apical  system  to  the  posterior 
end,  summit  situated  far  back.  Apical  system  eccentric,  posterior,  anterior  to 
the  summit. 

"Ambulacra  broad,  sunken;  anterior  petals  reaching  a  little  more  than  half 
way  to  the  margin;  posterior  laterals  very  short,  less  than  half  the  length  of 
the  anterior  pair,  sometimes  almost  circular  in  outline.  Ambulacral  pores 
elongated,  apparently  yoked. (?)  Mouth  opening  well  forward,  broad  two-lipped. 
Anus  high  up  on  the  truncated  posterior  end. 


122  University  of  California  Publications  in  Geology          [VOL.  8 

"Numerous  large  spines  much  like  those  of  Schizaster  have  been  found  at 
one  locality  in  the  Martinez,  but  if  they  belong  to  this  genus  at  all  they  were 
probably  derived  from  another  and  much  larger  species.  Tubercles  larger  on 
the  actinal  surface.  Peripetalous  fascicle  quite  distinct  on  one  specimen. 
Traces  of  what  appears  to  be  the  lateral  fascicle  have -been  seen  beneath  the  anus. 

"Though  crushed  fragments  of  this  species  have  been  known  to  the  writer 
for  some  years,  the  first  recognizable  specimens  were  discovered  by  the  members 
of  the  class  in  palaeontology  in  April,  1907. 

"Not  rare  in  the  Martinez  in  Contra  Costa  County.  Specimens  preserved 
only  as  impressions  or  casts,  usually  badly  crushed. ' ' 

Mr.  William  Kew  has  redescribed  this  species  as  follows : 

"Dimensions:  Twenty  forms  averaged  21.3mm.  in  length,  the  largest  being 
35  mm.  and  the  smallest  14  mm.  Of  nine  specimens  measured  the  average  height 
was  14mm.,  the  highest  being  22mm.  and  the  lowest  llmm.  The  ratio  of 
height  to  length  varies  somewhat.  As  a  rule  the  length  is  greater  than  the 
height.  The  average  ratio  of  eight  specimens  is  L:H  =  1:0.5999.  In  one  case 
the  ratio  is  L:H  =  1:1.1. 

' '  Test  deeply  and  distinctly  notched  anteriorly  by  the  ambulacra!  groove, 
continuing  around  to  the  mouth  of  the  actinal  side  with  slight  reduction  in  the 
size  of  the  groove.  Posteriorly  the  test  is  truncated  at  right  angles  to  the 
bottom.  Upper  surface  slopes  steeply  to  the  front  and  has  a  sharp  ridge 
running  from  the  apical  center  to  the  posterior  end  which  forms  the  summit 
of  the  test.  Apical  system,  eccentric,  anterior  to  the  summit.  Shell  of  test 
very  thin,  and  rarely  preserved. 

"Ambulacra  broad  and  deeply  sunken;  anterior  petal  reaches  almost  to 
margin;  anterior  laterals  a  little  over  half  way  and  posterior  petals  very  short 
and  almost  circular  in  outline.  Ambulacral  pores  elongated  and  consist  of 
two  series  of  three  rows  each,  the  middle  row  of  the  latter  alternating  with, 
and  overlapping  the  outside  ones.  Extremities  of  the  petals  closed.  Mouth 
opening  situated  about  two-thirds  the  distance  forward;  broad,  two-lipped. 
Anus  high  up  and  at  base  of  the  sharp  ridge  forming  the  summit. 

"Apical  shield  shows  madreporic  body  large  and  pentagonal  in  outline. 
Tubercles  small,  numerous  on  both  upper  and  lower  surface,  regularly  spaced. " ' 

BRYOZOA 

MEMBRANOPOKA(?),  sp. 

Incrustations  doubtfully  referred  to  the  genus  Menibranopora  were 
found  at  University  of  California  Locality  765  near  Lower  Lake,  Lake 
County,  California.  The  zooecia  are  hexagonal,  regularly  arranged  in 
quincunx  about  0.5  mm.  long  and  0.3  mm.  wide.  Surface  slightly 
concave  and  bordered  by  an  impressed  line. 

BRACHIOPODA 

RHYNCHONELLA(?),  sp. 

Plate  7,  figure  1 

A  small  brachiopod  was  found  at  University  of  California  Locality 
784  near  Lower  Lake,  which  has  been  referred  doubtfully  to  the  genus 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        123 

Rhynchonella.  Its  ventral  valve  is  marked  by  concentric  growth  lines 
and  by  microscopic  radiating  lines.  A  very  prominent  median  fold 
extends  from  the  center  of  the  shell  to  its  edge.  Cardinal  slopes 
gentle,  straight.  The  outer  portion  of  the  shell  appears  to  have  been 
removed. 

Dimensions. — Length,  9  mm. ;  height,  8  mm. ;  convexity,  3  mm. 

Occurrence. — Martinez  near  Lower  Lake. 


PELECYPODA 

LEDA  PACKARDI,  n.  sp. 
Plate  7,  figures  3a,  35 

Shell  thin,  marked  by  fine  rounded  concentric  lines,  short,  convex ; 
beaks  central,  small  but  prominent;  anterior  dorsal  margin,  slightly 
sloping;  posterior,  straight;  anterior  end  rounded;  posterior  end 
bluntly  pointed  with  apex  of  point  at  end  of  straight  posterior  dorsal 
margin;  base  rounded  from  anterior  to  middle  of  posterior  ventral 
margin;  from  this  point  the  slightly  curving  posterior  margin  slopes 
abruptly  upward  to  the  posterior  extremity.  This  species  differs  from 
all  the  other  California  ledas  in  shape  and  in  the  central  position  of 
its  beaks.  The  oddly  blunted  rostrum  is  another  distinguishing  feature. 

Dimensions. — Length  of  medium-sized  specimen,  10  mm. ;  height, 
5  mm. ;  convexity,  3  mm. 

Occurrence. — University  of  California  Locality  784;  Meretrix  dalli 
zone  north  of  Mount  Diablo  and  the  Trochocyathus  zitteli  zone  of  the 
Martinez  type  section,  near  Muir  Station. 

Named  in  honor  of  Mr.  Earl  Packard,  who  assisted  the  writer  in 
collecting  Martinez  fossils  in  Lake  County. 

LEDA  MILLERI,  n.  sp. 
Plate  7,  figure  4 

Shell  small,  moderately  convex;  beak,  prominent,  located  one-third 
of  the  distance  from  anterior  end.  Posterior  dorsal  edge  straight  with 
a  very  slight  slope  to  a  blunt  pointed  posterior  end.  Anterior  dorsal 
edge  straight  with  a  slightly  greater  slope  than  posterior  dorsal  edge. 
Ventral  margin  gently  convex.  This  margin  curves  sharply  toward 
the  two  pointed  extremities  of  the  shell. 

Dimensions. — Length,  9  mm. ;  height,  5  mm. ;  convexity,  2  mm. 

Occurrence. — University  of  California  Locality  1556. 

Named  in  honor  of  Dr.  L.  H.  Miller. 


124  University  of  California  Publications  in  Geology          [VOL.  8 

This  form  resembles  L.  packardi,  n.  sp.,  but  it  has  a  much  less 
height,  its  beak  is  more  anterior  and  its  length  is  greater.  It  some- 
what resembles  Malletia  chehalisensis  Arnold  in  shape. 


YOLDIA  GESTEKI,  n.  sp. 
Plate  7,  figure  5 

Shell  thin,  very  compressed;  anterior  end,  the  shorter,  and  equally 
rounded  above  and  below;  posterior  end,  slightly  longer,  pointed; 
posterior  dorsal  margin  very  slightly  concave;  escutcheon,  long,  nar- 
row; base,  rounded  and  most  prominent  beneath  beak,  from  which 
point  it  curves  regularly  to  the  pointed,  posterior  end;  beaks,  incon- 
spicuous; sculpture  consists  of  fine,  rounded  concentric  threads. 

This  species  is  not  as  convex  as  Y.  cooperi  Gabb  of  the  Miocene, 
its  posterior  dorsal  margin  is  not  as  concave  as  that  of  Y.  cooperi,  and 
the  decoration  is  much  finer. 

Dimensions. — Length,  28  mm. ;  height,  12  mm. ;  convexity,  2  mm. 

Occurrence. — Lake  County  at  University  of  California  localities 
784  and  790. 

Named  in  honor  of  Mr.  Clark  Gester,  Geologist,  Kern  Trading  and 
Oil  Company. 

The  outline  of  the  shell  is  restored  by  a  dotted  line. 


YOLDIA(?)   POWERSI,  n.  sp. 
Plate  7,  figure  6 

Shell  small,  thin,  elongated,  slightly  curved,  shaped  like  a  pruning 
knife.  Beak,  situated  a  fifth  of  the  length  from  the  anterior  end, 
prominent.  Anterior  end,  broadly  rounded;  posterior  end,  pointed 
sharply.  Anterior  dorsal  margin,  convex,  short ;  posterior  dorsal  edge, 
concave,  long.  An  impressed  groove  extends  on  the  cast  from  the 
beak  to  the  posterior  end  parallel  to  and  just  below  the  posterior  dorsal 
edge.  This  groove  divides  the  sharply  pointed  posterior  end.  Surface 
marked  by  rounded  concentric  lines  which  do  not  show  on  the  type. 

Dimensions. — Length,  10  mm. ;  height,  25  mm. ;  convexity,  1  mm. 

Occurrence. — Type  specimen  at  University  of  California  Locality 
1556,  lower  zone,  north  of  Mount  Diablo.  It  is  abundant  at  this 
locality  and  appears  to  be  characteristic  of  this  horizon.  It  is  easily 
distinguished  from  Y.  gesteri,  n.  sp.,  by  its  more  prominent  beaks, 


1914]      Dicker  son:  Fauna  of  the  Martinez  Eocene  of  California        125 

by  its  concave  dorsal  posterior  margin  and  by  its  short  anterior  margin. 
The  knife-like  form  identifies  it  readily. 

Named  in  honor  of  Mr.  J.  R.  Powers,  who  made  very  careful  collec- 
tions in  the  Martinez  at  Selby  Smelter. 


PINNA  BARROWSI,  n.  sp. 
Plate  8,  figure  3 

Description.— The  shape  of  the  shell  is  elongate-cuneate.  The  cross- 
section  of  the  shell  is  quadrate-oval.  The  valves  meet  on  their  dorsal 
margins  at  a  sharp  angle  which  increases  from  sixty  degrees  near  the 
base  to  ninety  degrees  near  the  beak.  The  ventral  portions  of  the 
valves  are  rounded.  Each  valve  presents  two  slopes :  a  flat,  dorsal 
and  a  slightly  convex,  ventral  which  meet  along  a  radial  line.  This 
line  divides  the  shell  so  that  the  flat  dorsal  slope  is  one-third  and  the 
rounded  ventral,  two-thirds  of  the  total  surface.  The  rounded  ventral 
slope  is  marked  in  its  central  half  by  approximately  eight  compressed 
and  slightly  elevated  radial  ribs  whose  interspaces  are  twice  their 
width,  and  by  eight  to  ten  concentric  rounded  ribs  in  its  marginal 
portion  as  well  as  radial  ribs,  thus  further  dividing  the  convex  slope 
into  equal  parts.  These  ribs  do  not  show  on  figured  specimen.  The 
flat  dorsal  slope  of  the  shell  is  ornamented  by  about  ten  compressed 
radial  ribs  which  are  separated  by  interspaces  two  times  as  wide.  The 
nearly  straight  posterior  end  makes  almost  a  right  angle  with  the 
ventral  margin. 

Dimensions. — Total  length,  unknown.  Length  of  specimen  whose 
beak  and  lower  margin  are  broken,  30  mm.,  width,  15  mm.,  approxi- 
mate. 

Occurrence. — Two  and  one-half  miles  south  of  Muir  Station  and 
one-half  mile  east  of  the  road  which  crosses  the  Briones  Hills  going 
south  from  Muir  Station,  on  north  slope  of  a  small  tributary  of  a 
tributary  of  Arroyo  del  Hambre.  Elevation,  550  feet.  About  100 
yards  north  of  Monterey-Martinez  contact,  University  of  California 
Locality  1547,  and  at  University  of  California  Locality  243. 

Notes. — Pholadomya  nasuta,  Trochocyathus  zitteli,  Urosyca  cau- 
data,  Siphonalia(f)  lineata,  and  many  other  Martinez  species  are 
associated  with  this  form.  Pinna  barrowsi  has  two  kinds  of  ornamen- 
tation while  P.  l)rewerii  has  but  radial  ribs.  The  gore  or  plait  which 
divides  both  valves  of  P.  breiverii  is  approximately  central,  while  the 


126  University  of  California  Publications  in  Geology          [VOL.  8 

radial  line  which  sets  off  the  flat  dorsal  portion  of  P.  barrowsi  is  not 
central  nor  is  it  deeply  eroded. 

This  Pinna  is  also  found  in  the  lower  Tejon,  southwest  of  Mount 
Diablo,  near  Pine  Creek,  at  University  of  California  Locality  1489. 

Named  in  honor  of  Mr.  A.  L.  Barrows. 


LIMA(?)   CLAYTONENSIS,  n.  sp. 
Plate  7,  figures  9a,  9& 

Shell  inflated,  with  radial  sculpture;  rounded  and  almost  sym- 
metrical. Ratio  of  length  to  height  about  .65  to  1.  Beak  prominent, 
acute,  and  in  some  specimens  compressed.  Hinge  line  short  and 
straight  with  about  twelve  small  striations  perpendicular  to  hinge 
line.  These  striations  may  be  plications  within  the  shell  wall,  revealed 
by  th  breaking  away  of  the  inner  shell  layer.  Area,  narrowly  elliptical 
and  central.  Basal  margin,  rounded.  Eibs — about  thirteen  in  number 
— are  acute-angled  and  beaded;  the  interspaces  are  the  same  in  width 
as  the  ribs. 

Dimensions. — Length,  2.5  mm. ;  height,  3.8  mm. 

Occurrence. — Martinez  Group,  two  miles  due  east  of  Clayton  in 
beds  near  base,  University  of  California  Locality  1592.  It  also  occurs 
at  localities  1546  and  1557.  (See  table  of  localities.) 

The  various  features  described  were  recognized  from  a  study  of 
four  different  specimens.  This  little  shell  is  quite  characteristic  of  the 
basal  beds  or  beds  about  100  feet  above  the  base  at  its  type  localities. 
It  is  one  of  the  few  species  found  in  the  Martinez  shales. 

Named  for  its  occurrence  near  Clayton. 


LIMA(?)   HASELTINEI,  n.  sp. 
Plate  8,  figure  2;  plate  9,  figure  11 

Shell  large,  slightly  oblique,  nearly  equivalve,  moderately  convex; 
beak  prominent,  pointed,  anterior,  prosogyrate;  hinge,  edentulous, 
long,  straight;  ears  not  markedly  set  off  from  rest  of  shell,  the  pos- 
terior one  being  the  larger ;  anterior  end  broadly  rounded ;  posterior, 
slightly  truncated;  ventral  margin,  arcuate;  decoration  consists  of 
numerous  squarish  radial  ribs  with  very  narrow  interspaces. 

Dimensions. — Height  of  large  specimen,  130  mm. ;  length,  135  mm. ; 
convexity,  27  mm. 


1914]       Dicker  son:  Fauna  of  the  Martinez  Eocene  of  California        127 

Occurrence. — University  of  California  localities  1540  and  1580, 
both  being  in  the  Trocliocyathus  zitteli  zone  of  the  area  north  of  Mount 
Diablo.  The  Stanford  University  class  in  field  geology,  -1910,  also 
found  this  form  in  the  Martinez  just  north  of  the  Calabasas  Quad- 
rangle. This  is  the  largest  lamellibranch  thus  far  reported  from  either 
the  Tejon  or  Martinez  on  this  coast. 

Named  in  honor  of  my  friend,  Mr.  R.  S.  Haseltine. 


OSTREA  BUWALDANA,  n.  sp. 
Plate  9,  figure  4 

Shell,  medium,  with  thick  shell  substance,  only  slightly  oblique, 
elliptical;  upper  valve  flat;  lower  valve  deep,  convex  and  marked  by 
rough,  squamose  growth  lines  and  about  six  strong  radiating  ribs. 
Muscular  scar  is  reniform,  nearly  central.  Internal  margins  of  some 
specimens  distinctly  pitted  on  both  sides  of  beaks  in  casts  of  this 
species.  Occasionally  small  tooth-like  projections  are  seen  on  the 
shell  itself  on  both  sides  of  the  beaks. 

Dimensions. — Length,  35  mm. ;  height,  48  mm. ;  convexity  of  lower 
valve,  5  mm. 

Occurrence. — University  of  California  localities  790  near  Lower 
Lake  and  693  at  San  Pedro  Point,  San  Mateo  County,  California. 

It  differs  from  0.  idriaensis  Gabb  in  that  the  lower  valve  is  marked 
by  radiating  ribs.  Its  shape  is  more  angular  than  that  of  0.  idriaensis. 
The  type  is  from  University  of  California  Locality  790. 

Named  in  honor  of  Mr.  J.  P.  Buwalda. 


OSTKAEA  WEAVERI,  n.  sp. 
Plate  9,  figure  3 

Shell  medium  in  size,  subequivalve,  irregularly  oval,  contorted  near 
the  beaks,  unattached.  Surface  marked  by  regular  squamose  lines  of 
growth.  Beak  twisted  and  terminating  at  the  anterior  dorsal  margin. 
The  upper  half  is  subglobose  while  the  lower  half  is  flat  or  slightly 
concave.  These  two  portions  are  very  deeply  set  off  and  the  species  is 
readily  determined  by  this  characteristic.  In  the  lower  valve,  the 
bulging  of  the  upper  portion  is  less  prominent.  The  growth  lines  are 
remarkably  even  for  this  genus. 


128  University  of  California  Publications  in  Geology          [VOL.  8 

Dimensions. — Length,  23  mm. ;  height,  37  mm. ;  convexity,  11  mm. 

Occurrence. — University  of  California  localities  781  and  790  near 
Lower  Lake  and  1888  near  Selby  Station. 

Named  in  honor  of  Professor  Charles  E.  Weaver  of  the  University 
of  Washington. 


PECTEN  (CHALAMYS?),  sp. 
Plate  9,  figure  6 

Shell  minute,  subcircular,  equilateral,  slightly  ventricose.  Eight 
valve  with  exterior  surface  ornamented  by  ten  squarish  ribs,  the 
middle  two  being  decidedly  dichotomous;  interspaces  channeled  and 
about  half  as  wide  as  ribs;  ears  nearly  equal,  markings,  obscure. 

Dimensions. — Length,  3  mm. ;  height,  2.5  mm. ;  convexity,  1  mm. 

Occurrence. — Only  one  specimen  was  found,  at  University  of  Cali- 
fornia Locality  790. 

It  can  be  distinguished  from  all  other  Eocene  pectens  on  this  coast 
by  its  small  number  of  external  ribs  and  by  the  shape  of  these  ribs. 


MODIOLUS  BAKERI,  n.  sp. 
Plate  9,  figure  8 

Shell,  medium  in  size,  thick;  beak  small  but  prominent,  about  a 
sixth  of  the  length  from  the  anterior  end  which  is  narrowly  rounded ; 
posterior  end,  broadly  rounded;  cardinal  margin,  straight;  ventral 
margin,  slightly  rounded;  umbonal  ridge  prominent,  rounded,  and 
extending  to  the  posterior  end  below  its  center.  A  marked  concavity 
in  larger  specimen  figured  extends  from  the  beaks  to  the  middle  of  the 
ventral  margin.  Surface  marked  by  lines  of  growth. 

Dimensions. — Smaller  specimen  :  length,  17  mm. ;  height,  8  mm. ; 
convexity,  4  mm. 

Occurrence. — University  of  California  localities  243,  near  Muir 
Station,  and  1556,  lower  zone  of  Martinez  north  of  Mount  Diablo. 

This  species  appears  to  grow  more  robust  with  increase  in  age.  It 
resembles  Modiolus  major  (Gabb),  but  its  beak  is  not  quite  so  nearly 
terminal.  The  marked  concavity  on  the  shell  also  aids  in  distinguish- 
ing it.  It  differs  in  shape  and  in  lack  of  ornamentation  from  M. 
ornatus  (Gabb). 

Named  in  honor  of  Mr.  Charles  Lawrence  Baker,  Geologist, 
Southern  Pacific  Company. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        129 

CUSPID AEIA  HANNIBALI,  n.  sp. 
Plate  9,  figure  10 

Shell  small ;  beaks  subcentral,  of  medium  size,  approximate,-promi- 
nent  and  slightly  curved  anteriorly.  Posterior  end  is  about  one-third 
the  height  of  the  shell  and  is  produced.  The  posterior  portion  of  the 
shell  is  marked  off  sharply  from  the  anterior  by  four  transverse 
rounded  ribs  which  extend  from  the  beak  to  the  base.  The  interspaces 
are  somewhat  wider  than  the  ribs.  In  two  of  these  interspaces  a  riblet 
is  found.  These  ribs  do  not  extend  to  the  posterior  tip  but  end  where 
the  posterior  portion  suddenly  narrows,  thus  dividing  the  shell  into 
three  distinct  parts.  The  anterior  portion  is  rounded  and  its  base  is 
regularly  convex.  The  anterior  portion  is  marked  only  by  concentric 
lines  of  growth.  A  sharp  ridge  extends  from  the  beak  to  the  dorsal 
edge  of  the  posterior  end  and  a  sharp  groove  is  found  between  the 
hinge  line  and  this  ridge.  Interior  unknown. 

Dimensions. — Length,  10  mm.  ( ?)  ;  height,  5  mm ;  width  of  produced 
anterior  portion  near  ribs,  2  mm. 

Occurrence. — University  of  California  Locality  1547,  Martinez 
Group,  Trochocyathus  zitteli  zone. 

This  specimen  differs  from  Neaera  dolabraeformis  Gabb,  which  is 
reported  from  his  "Cretaceous  B,"  in  the  following  ways :  (1)  Its  beak 
is  far  less  prominent.  (2)  Its  ribs  are  confined  to  the  central  third 
of  the  shell,  only,  while  the  radial  ribs  of  N.  dolabraeformis  cover  all 
the  shell  but  the  produced  posterior  end.  (3)  N.  dolabraeformis  lacks 
the  prominent  ridge  extending  from  the  beak  to  the  anterior  end. 

This  specimen  was  found  by  Mr.  Hannibal,  who  accompanied  the 
writer  to  the  locality.  The  species  is  associated  with  Trochocyathus 
zitteli,  Pholadomya  nasuta,  Urosyca  caudata,  Cucullaea  mathewsonii, 
Glycimeris  veatchii,  var.  major  and  Cardium  cooperi. 

Named  in  honor  of  Mr.  Harold  Hannibal. 


CRASSATELLITES    STUDLEYI,    n.  sp. 

Plate  10,  figure  1 

Shell  thick,  high,  suborbicular ;  beaks  prominent,  prosogyrate, 
moderately  high,  approximate,  and  situated  back  of  mid-length.  Pos- 
terior dorsal  margin  slightly  convex,  sloping  to  the  broadly  rounded 
posterior  end.  A  well-marked,  narrow  escutcheon  is  set  off  by  two 
acute  ridges  from  the  rest  of  the  shell.  Anterior  dorsal  margin  nearly 


130  University  of  California  Publications  in  Geology          [VoL-  8 

straight,  longer  than  posterior  dorsal  margin,  sloping  more  steeply 
than  the  posterior  dorsal  margin  to  a  narrowly  rounded  anterior  end. 
A  narrow  lunule  inset  in  this  margin  is  slightly  concave  under  the 
beaks.  Ventral  margin,  rounded.  A  marked  rounded  umbonal  slope, 
which  extends  to  a  point  between  the  posterior  end  and  the  ventral 
margin,  divides  the  shell  into  a  posterior  and  an  anterior  part.  The 
posterior  portion  is  a  nearly  flat  surface  while  the  anterior  is  convex. 

Dimensions. — Length,  25  mm. ;  height,  22  mm. ;  convexity,  7  mm. 

Occurrence. — Trochocyathus  zitteli  zone  north  of  Mount  Diablo 
near  University  of  California  Locality  1540. 

This  species  is  distinguished  from  C.  grandis  by  its  greater  con- 
vexity, by  its  marked  umbonal  slope  and  by  lack  of  trigonal  shape. 
It  is  distinguished  from  C.  stewartvillensis,  n.  sp.,  by  its  more  central 
position  of  beaks  and  by  its  umbonal  slope. 

Named  in  honor  of  Mr.  C.  K.  Studley. 


CRASSATELLITES    STEWARTVILLENSIS,    n.  sp. 
Plate  10,  figure  3 

Shell  large,  thick,  trigonal;  beaks  rounded,  prosogyrate,  approxi- 
mate, situated  a  third  of  the  distance  from  the  anterior  end.  Anterior 
end  broadly  rounded;  posterior,  rounded  but  narrower  than  anterior. 
Posterior  dorsal  margin,  nearly  straight  sloping  gently  to  the  posterior 
end ;  anterior  dorsal  margin,  short  and  steep ;  ventral  margin,  nearly 
straight.  A  prominent  heart-shaped  lunule  is  set  off  by  a  rounded 
ridge.  The  escutcheon  is  long  and  narrow  and  very  definitely  limited 
by  two  sharp  angular  ridges  which  extend  along  most  of  its  length. 
Surface  marked  by  growth  lines  only. 

Dimensions. — Length  of  broken  specimen,  28  mm. ;  height,  25  mm. 

Occurrence. — Found  at  University  of  California  Locality  1540, 
Trochocyathus  zitteli  zone,  north  of  Mount  Diablo. 

This  form  differs  from  C.  grandis  Gabb  in  the  less  central  position 
of  the  beak,  in  the  slopes  of  the  dorsal  margins  and  in  the  less  convex 
ventral  margin.  It  differs  from  C.  unioides  Stanton  in  beak  position 
and  in  its  less  elongate  form. 

Named  for  the  old  coal-mining  village  of  Stewartville,  near  which 
it  was  found. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        131 

CRASSATELLITES   CLAYTONENSIS,   n.  sp. 
Plate  10,  figures  4a,  4b 

Shell,  elongate  oval ;  beak,  prominent  and  located  one-fourth  the 
distance  from  anterior  end;  posterior  dorsal  margin  straight,  with 
gentle  slope  to  posterior ;  anterior  dorsal  margin  short,  concave ; 
anterior  end  rounded ;  posterior  end,  truncated.  A  rounded  umbonal 
slope  extends  to  the  junction  of  the  posterior  end  and  the  arcuate 
ventral  margin.  Surface  marked  in  umbonal  region  by  prominent, 
rounded,  concentric  ribs.  The  specimens  are  imbedded  in  the  matrix 
so  that  a  complete  hinge  cannot  be  exposed,  but  the  cardinal  teeth 
appear  to  be  those  of  Crassatellites. 

Dimensions. — Length,  11  mm. ;  height,  8.5  mm. ;  convexity,  3  mm. 

Occurrence. — University  of  California  localities  1558,  basal  Mar- 
tinez beds  north  of  Mount  Diablo,  and  1547,  Trochocyathus  zitteli 
zone  near  Muir  Station. 

Named  for  the  town  of  Clayton,  near  which  one  of  the  type 
specimens  was  found. 

CAEDITA  VENERIFOEMIS  Gabb 

Geological  Survey  of  California,  Palaeontology,  vol.  1,  p.  215,  1864. 

" Shell  small,  very  convex,  subquadrate;  beaks  rather  large,  strongly  in- 
curved; cardinal  margin  nearly  straight;  posterior  end  obliquely  and  convexly 
truncated;  anterior  end  deeply  excavated  under  the  beaks,  produced  and  nar- 
rowly rounded  below;  base  broadly  rounded;  hmule  broad,  deeply  impressed. 
'Surface  marked  by  about  forty  fine,  acute,  radiating,  ribs,  with  sometimes  an 
intercalated  one  arising  in  the  middle  of  the  shell,  and  becoming  as  large  as 
the  others  before  it  reaches  the  base;  these  are  most  numerous  anteriorly,  where 
all  of  the  ribs  are  smaller  than  on  the  middle;  margin  strongly  crenulated. 

"Locality:  West  of  Martinez.    Martinez  Group." 

This  species  has  the  same  acute  ribs  as  the  young  of  V.  planicosta, 
and  the  same  variations  in  form.  Some  specimens  found  in  the  basal 
Martinez  north  of  Mount  Diablo  vary  from  an  elongate  quadrate  form 
to  a  high  form  similar  to  the  high  variety  of  V.  planicosta. 

PHACOIDES  QUADKATA,  n.  sp. 
Plate  10,  figure  6 

Shell  thin,  compressed,  markedly  quadrate,  high;  beaks  rounded, 
prosogyrate;  posterior  dorsal  margin  straight,  sloping  moderately  to 
the  straight  posterior  end,  which  is  nearly  parallel  to  altitude  line; 


132  University  of  California  Publications  in  Geology          [VOL.  8 

anterior  dorsal  margin  very  slightly  convex;  anterior  end  nearly 
straight;  ventral  margin  rounded;  sculpture  consists  of  raised  sharp 
incremental  lines  with  interspaces  about  three  times  their  width. 

Dimensions. — Length,  10  mm. ;  height,  10  mm. ;  convexity,  1.5  mm. 

Occurrence. — University  of  California  Locality  784  near  Lower 
Lake. 

The  quadrate  shape  of  this  species  is  quite  sufficient  to  distinguish 
it  from  other  members  of  the  genus. 

PHACOIDES  MUIBENSIS,  n.  sp. 
Plate  10,  figures  lla,  116 

Shell  small,  suborbicular,  convex;  beaks  nearly  central;  in  some 
specimens  slightly  posterior  to  the  center.  Lunule  narrow,  small ; 
escutcheon  long,  narrow ;  posterior  dorsal  margin  nearly  straight ; 
anterior  dorsal  margin  slightly  excavated  under  the  beaks;  anterior 
and  posterior  extremities  subtruncate;  ventral  margin  broadly 
rounded.  Surface  is  marked  by  strong  concentric  growth  lines  and 
by  a  very  faint,  narrow,  posterior  furrow  which  is  absent  in  young 
specimens. 

This  species  differs  from  Phacoides  turneri  (Stanton)  in  the  trun- 
cation of  the  extremities,  in  the  slightly  posterior  position  of  the  beak 
and  in  the  lesser  prominence  of  the  posterior  furrow. 

Dimensions. — Height,  14.5  mm.;  length,  15.5  mm;  convexity, 
3.5  mm. 

Occurrence. — University  of  California  Locality  243. 

Named  for  its  occurrence  near  Muir  Station. 

PHACOIDES  DIABOLI,  n.  sp. 

Plate  10,  figure  7 

Shell  thin,  equivalve,  suborbicular,  nearly  equilateral ;  beaks  promi- 
nent, prosogyrate,  central;  valves  convex;  lunule  narrow  and  extend- 
ing half  the  length  of  the  straight  horizontal  anterior  dorsal  margin ; 
escutcheon  narrow,  two-thirds  the  length  of  the  straight  sloping  pos- 
terior dorsal  margin  and  set  off  in  each  valve  by  a  high,  sharp  ridge 
from  rest  of  shell.  A  rounded  ridge  extends  from  the  beaks  to  the 
middle  of  the  posterior  end;  the  portion  of  shell  between  the  umbonal 
ridge  and  the  ridge  bordering  the  escutcheon  is  slightly  concave; 
sculpture  consists  of  sharp  concentric  lamellae  with  interspaces  about 
three  times  their  width. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        133 

Dimensions. — Length,  23  mm. ;  height,  18  mm. ;  convexity,  4  mm. 

Occurrence. — Common  at  University  of  California  Locality  340, 
Martinez  Group  southwest  of  Mount  Diablo. 

The  sculpture  resembles  that  of  P.  acutilineatus  (Conrad)  but  its 
height  is  proportionally  much  less  than  that  of  P.  acutilineatus.  Its 
long  lunule  and  escutcheon  are  also  distinctive  features. 

Named  for  its  occurrence  near  Mount  Diablo. 


DOSINIA(?)  LAWSONI,  n.  sp. 
Plate  10,  figure  9 

Shell,  medium  in  size,  subglobular,  very  convex,  with  full  rounded 
beaks  centrally  placed ;  anterior  dorsal  margin  excavated  under  beaks, 
where  a  small  lunule  is  found ;  posterior  dorsal  margin  nearly  straight, 
with  steep  slope  to  the  rounded  posterior  end;  anterior  end  narrowly 
rounded;  ventral  margin  arcuate;  surface  smooth  or  marked  by  fine 
incremental  lines  only. 

Dimensions. — Length,  16  mm. ;  height,  14  mm. ;  convexity,  4.5  mm. 

Occurrence. — University  of  California  localities  243  and  340,  Mar- 
tinez limestone  southwest  of  Mount  Diablo. 

The  type  is  a  small  specimen  used  on  account  of  its  fair  preserva- 
tion. The  species  is  far  more  convex  than  the  other  Eocene  species  of 
this  genus.  In  this  respect  it  resembles  D.  inflata  Gabb  of  the  Chico, 
but  the  shape  and  position  of  the  beaks  is  entirely  different. 

Named  in  honor  of  Professor  A.  C.  Lawson,  University  of  Cali- 
fornia. 

VENUS  (I),  sp. 
Plate  10,  figure  10 

Shell  thick  subtriangular,  convex ;  beaks  very  high,  nearly  central ; 
posterior  dorsal  margin  gently  convex,  sloping  steeply  to  the  rounded 
posterior;  anterior  margin  very  concave  and  abrupt;  ventral  margin 
rounded;  lunule  indistinct. 

Dimensions. — Length,  26  mm. ;  height,  28  mm. ;  convexity,  7  mm. 

Occurrence. — University  of  California  localities  790,  vicinity  of 
Lower  Lake,  and  340,  southwest  of  Mount  Diablo. 

The  specimen  is  a  cast,  hence  the  generic  reference  is  doubtful.  It 
differs  from  V.  lenticularis  Gabb  of  the  Chico  in  that  the  beak  is 
considerably  higher  and  the  posterior  dorsal  margin  is  decidedly 


134  University  of  California  Publications  in  Geology          [VOL.  8 

convex  and  not  straight.  The  anterior  and  posterior  dorsal  margins 
of  V.  aequilateralis  Gabb  are  straight,  while  those  of  Venus(f),  sp., 
are  concave  and  convex  respectively. 


MERETRIX  STANTONI,  n.  sp. 
Plate  11,  figures  la,  Ib 

Meretrix,  sp. — Stanton,  T.  W.,  The  Faunal  Relations  of  the  Eocene  and 
Upper  Cretaceous  on  the  Pacific  Coast,  17th  Ann.  Rept.,  U.  S.  Geolog- 
ical Survey,  p.  1042,  1896. 

Dr.  Stanton  in  his  paper  on  the  Eocene  and  Upper  Cretaceous  of 
the  Pacific  Coast  describes  a  Meretrix,  but  does  not  give  it  a  specific 
name.  Since  this  form  is  abundant  in  the  basal  beds  north  of  Mount 
Diablo  and  the  Martinez  in  Lake  County  at  Lower  Lake,  and  is  dis- 
tinctive, it  is  thought  best  to  name  it  specifically.  Dr.  Stanton 's 
description  is  as  follows : 

"One  of  the  most  abundant  species  at  the  locality  one  mile  southeast  of 
Lower  Lake  is  a  venerid  apparently  belonging  to  the  genus  Meretrix  and  closely 
resembling  the  original  figure  of  M.  hornii  Gabb,  but  as  Gabb  discredited  that 
figure  when  it  was  published  and  his  later  figure  and  the  specimens  preserved 
in  the  Academy  of  Natural  Sciences,  Philadelphia,  are  not  at.  all  like  it,  our 
fossils  can  not  be  identified  with  his  species.  Possibly  this  will  prove  to  be 
a  new  species,  but  I  shall  not  venture  to  name  it  until  several  of  Gabb 's 
venerid  species  represented  by  conventionalized  figures  are  better  known.  Shell 
subtriangular,  moderately  convex;  with  thin  test;  beaks  prominent,  considerably 
in  advance  of  the  middle,  lunule  small,  deeply  impressed;  dorsal  margin  slightly 
convex  behind  the  beak,  sloping  rapidly  to  the  narrowly  rounded  posterior  end; 
anterior  end  broadly  rounded;  ventral  margin  forming  a  regular  curve;  surface 
marked  by  closely  arranged,  rather  prominent  ridges  and  furrows  which  vary 
considerably  in  size.  The  numerous  specimens  collected  show  considerable 
variation  in  relative  length  of  the  shells,  but  this  feature  does  not  seem 
sufficiently  constant  for  specific  separation.  The  dimensions  of  the  largest 
specimens:  Length,  43mm.,  height,  31mm.;  convexity  of  single  valve  about 
8  mm.  The  corresponding  measurements  of  a  smaller  specimen  of  the  short 
variety  are  27,  23,  and  6  mm.,  respectively. ' ' 

M.  stantoni,  which  is  probably  related  to  M.  hornii,  is  more  acute 
posteriorly  and  the  anterior  end  is  higher  above.  The  concentric  lines 
of  M.  hornii  are  less  numerous  and  more  prominent  than  those  of 
M.  stantoni.  This  shell  apears  to  be  distinct  from  the  short  species, 
M.  dalli,  described  below.  It  is  very  abundant  in  the  lower  beds  of 
the  Martinez  formation  at  University  of  California  Locality  1556, 
Martinez  Group,  Mount  Diablo  Quadrangle,  one  and  one-eighth  miles 
south  of  Stewartville  in  the  lower  beds  ten  feet  above  the  Martinez- 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        135 

Chico  contact.    Elevation,  1050  feet.    E.  side  of  the  NW  %  of  Section 
15,  R.  1  E,  T.  1  N,  Mount  Diablo   Baseline  and  Meridian. 


MERETRIX  DALLI,  n.  sp. 
Plate  11,  figures  2a,  25 

Shell  trigonal,  convex  with  very  thin  test;  beaks  prominent,  in- 
curved and  bent  forward,  situated  slightly  in  advance  of  the  center; 
posterior  dorsal  margin  slightly  convex  and  sloping  steeply  to  the 
rounded  posterior  end;  anterior  dorsal  margin  concave  under  the 
beaks,  rounded  in  advance;  ventral  margin  gently  convex;  lunule 
small;  escutcheon  long  and  very  narrow;  sculpture  consists  of  fine 
incremental  lines  only. 

Dimensions. — Length,  22  mm. ;  height,  17  mm. ;  convexity,  6  mm. 

Occurrence. — This  species  occurs  abundantly  in  the  Martinez  near 
Lower  Lake.  The  type  specimen  was  found  at  University  of  California 
Locality  790.  It  is  also  found  in  the  basal  Martinez  north  of  Mount 
Diablo. 

M .  dalli,  n.  sp.,  differs  from  M.  stantoni,  n.  sp.,  in  its  much  greater 
convexity,  greater  height  and  shorter  length,  and  the  concavity  of  the 
anterior  dorsal  margin  is  much  greater.  It  differs  from  M.  hornii 
Gabb  in  shape  and  sculpture.  M.  gabbi  Arnold  is  higher  and  inequi- 
laterally  trigonal,  while  M.  dalli,  n.  sp.,  is  equilaterally  trigonal.  M. 
ovalis  Gabb  and  M.  uvasana  Gabb  have  very  different  shapes  than 
M.  dalli,  n.  sp. 

MERETEIX,  sp. 
Plate  11,  figure  3 

Shell  very  convex,  trigonal,  beaks  anterior  being  one-third  of  total 
length  from  anterior  end;  posterior  dorsal  margin  but  slightly  convex 
and  sloping  to  a  narrow  posterior  end ;  anterior  dorsal  margin,  concave 
with  a  well-marked,  large,  heart-shaped  lunule,  anterior  end  broadly 
rounded ;  ventral  margin,  arcuate ;  sculpture,  fine  lines  of  growth  only. 

Dimensions. — Length,  12  mm. ;  height,  10  mm. ;  convexity,  3  mm. 

Occurrence. — University  of  California  Locality  1556,  basal  Mar- 
tinez beds  north  of  Mount  Diablo,  and  University  of  California 
Locality  340  southwest  of  Mount  Diablo. 

This  form,  though  shorter,  resembles  Meretrix  hornii  Gabb  in 
shape,  but  lacks  its  marked  ribbing.  It  differs  from  M.  stantoni,  n.  sp., 
in  its  larger  lunule  and  greater  convexity. 


136  University  of  California  Publications  in  Geology          [VOL.  8 

MACROCALLISTA(?)    PACKI,   n.  sp. 
Plate  11,  figure  4 

Shell  elongate-oval  in  shape;  beaks  prominent,  being  situated  one- 
third  the  distance  from  anterior  end ;  posterior  dorsal  margin  straight, 
sloping  gently  to  a  narrowly  rounded  posterior  end;  anterior  dorsal 
margin  excavated  under  the  beaks,  unusually  long;  anterior  end 
broadly  rounded;  ventral  margin  slightly  arcuate;  shell  substance, 
thin;  surface  smooth. 

Dimensions. — Length,  27  mm. ;  height,  15  mm. ;  convexity,  4  mm. 

Occurrence. — University  of  California  Locality  790,  vicinity  of 
Lower  Lake,  1580,  Lower  Martinez  beds  north  of  Mount  Diablo,  and 
in  the  Eocene  of  San  Pedro  Point,  San  Mateo  County. 

This  species  can  readily  be  distinguished  from  all  other  venerid 
species  on  this  coast  by  its  elongate  form  and  by  its  long  anterior 
dorsal  margin. 

Named  in  honor  of  Mr.  Robert  Pack,  Geologist,  U.  S.  Geological 
Survey. 

PAPHIA(?)   CLAEKI,  n.  sp. 
Plate  11,  figure  6 

Shell  long,  narrow,  inequilateral;  beaks  small,  placed  a  third  of 
the  distance  from  the  anterior  end;  posterior  dorsal  margin  slightly 
convex,  sloping  to  a  narrow  rounded  posterior  extremity;  anterior 
dorsal  margin  concave  with  a  very  small  lunule  upon  it ;  sculpture, 
small,  regularly  rounded  ribs. 

Dimensions. — Length,  9.5  mm. ;  height,  6  mm. ;  convexity,  2  mm. 

Occurrence. — University  of  California  localities  790  and  784, 
vicinity  of  Lower  Lake ;  basal  Martinez  and  Trochocyathus  zitteli  beds 
north  of  Mount  Diablo. 

This  form  resembles  Tapes  conradiana  Gabb  closely,  but  is  a  shorter 
form  with  finer  ribbing.  The  specimens  found  are  all  small  ones. 

Named  in  honor  of  Mr.  B.  L.  Clark,  Instructor  in  Palaeontology, 
University  of  California. 

TELLINA  HERNDONENSIS,  n.  sp. 

Plate  11,  figure  9 

Shell  moderate  in  size,  longer  than  high;  beaks  nearly  central, 
prominent.  Posterior  dorsal  margin,  straight  with  slightly  greater 
slope  than  the  posterior  dorsal  margin.  Posterior  end  narrowly 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        137 

rounded;  anterior  broadly  rounded;  ventral  margin  nearly  straight. 
A  marked,  rounded  ridge  nearly  parallels  the  posterior  dorsal  margin. 

Dimensions. — Length,  13.5mm.;  height,  10mm.;  convexity,  2mm. 

This  species  is  very  similar  in  form  to  T.  hoffmaniana  Gabb  which 
was  figured  in  volume  1,  Palaeontology  of  California  (see  fig.  1130, 
pi.  22),  but  Gabb  has  undoubtedly  confused  two  different  species  in 
this  case,  as  figure  133  is  very  different.  All  the  specimens  from 
Pence's  Ranch  in  the  University  of  California  Cretaceous  collections 
correspond  to  figure  133,  which  we  will  regard  as  T.  hoffmaniana 
Gabb,  a  Chico  form. 

Occurrence. — University  of  California  Locality  784. 

Named  for  its  occurrence  near  Herndon  Creek,  Lake  County,  Cali- 
fornia. 


TELLINA  PACKABDI,  n.  sp. 
Plate  11,  figure  11 

Shell  large,  nearly  equilateral,  compressed;  anterior  end  evenly 
rounded ;  posterior  end  angulated  in  middle ;  beak  central,  small ;  sides 
making  an  angle  of  110°  at  the  umbo;  anterior  dorsal  margin  slightly 
convex  with  abrupt  slope  nearly  equal  to  that  of  the  straight  posterior 
dorsal  margin;  ventral  margin  broadly  rounded;  surface  marked  by 
concentric  lines  of  growth. 

Dimensions. — Length,  36  mm. ;  height,  30  mm. ;  convexity,  4  mm. 

Occurrence. — University  of  California  localities  790  and  784,  near 
Lower  Lake. 

This  species  differs  from  T.  parilis  Gabb,  T.  aequalis  Gabb,  and 
T.  lorenzoensis  Arnold  in  its  smaller  umbonal  angle  and  in  its  pro- 
portionally greater  height. 

Named  in  honor  of  Mr.  Earl  Packard. 


TELLINA  PERRINI,  n.  sp. 

Plate  11,  figure  8 

Shell  long,  very  narrow ;  beaks  small  and  located  two-fifths  of  the 
shell-length  from  the  anterior  end ;  anterior  dorsal  slope  straight,  with 
gentle  slope  toward  the  rounded  anterior  end;  the  steeper  posterior 
dorsal  slope  is  slightly  concave  from  beaks  outward  to  half  its  length 
and  then  it  becomes  convex;  posterior  extremity  very  angular;  basal 
margin  narrowly  arcuate;  lunule  and  escutcheon,  long  and  narrow. 


138  University  of  California  Publications  in  Geology          [VOL.  8 

A  straight  line  which  extends  from  the  beaks  to  the  sharp  angular 
posterior  extremity  marks  a  prominent  umbonal  slope.  The  space 
between  this  slope  and  the  posterior  dorsal  margin  is  decidedly  con- 
cave. Surface  of  shell  marked  by  concentric  lines  of  growth. 

Dimensions. — Length,  33  mm. ;  height,  11  mm. ;  convexity,  2  mm. 

This  species  can  be  distinguished  from  all  other  West  Coast  Eocene 
forms  of  the  genus,  Tellina,  by  its  great  length  and  marked  umbonal 
slope. 

Named  in  honor  of  Professor  James  Perrin  Smith  of  Stanford 
University. 

TELLINA  KEWI,  n.  sp. 

Plate  12,  figure  1 

Shell  medium,  thin,  broad,  slightly  convex,  very  inequilateral,  but 
longer  than  high ;  beak  small,  incurved ;  posterior  and  anterior  dorsal 
margins  nearly  straight,  the  posterior  sloping  the  more  abruptly; 
anterior  end  very  broadly  rounded;  posterior  end  produced  and 
pointed;  ventral  margin  broadly  rounded,  more  prominent  beneath 
the  beaks,  and  curving  from  this  point  abruptly  upward  to  the  pointed 
posterior  end.  Surface  plain,  or  marked  with  simple  growth  lines. 
This  species  was  probably  described  and  refigured  by  Gabb32  in  the 
second  volume  of  Palaeontology  of  California,  as  Tellina  hoffmaniana. 
He  says :  ' '  This  rather  variable  species  is  extremely  common  in  the 
Martinez  group  at  Martinez,  and  has  been  found  in  the  Chico  group 
at  Pence's  Ranch,  as  well  as  in  the  Tejon  group  at  Griswold's.  I 
have  now  a  single  specimen  from  the  latter  group  from  Martinez 
associated  with  Turritella  uvasana,  and  other  characteristic  species. 
The  present  figure  illustrates  a  common,  and  one  of  the  most  marked 
forms  of  the  Martinez  group,  Martinez,  from  the  same  bed  with 
Pugnellus  hamulus."  The  old  State  Geological  Survey  specimens  now 
in  the  collection  of  the  University  of  California  show,  upon  careful 
examination,  a  decided  difference  between  the  Chico  forms  from 
Pence's  Ranch  and  the  ones  from  Martinez.  Several  forms  which 
Gabb  described  from  Division  A  near  Martinez  have  since  been  proved 
to  be  Martinez  or  Tejon  forms.  The  appearance  of  the  Chico  and 
Martinez  sandstones  are  sometimes  very  much  alike  and,  if  he  collected 
near  the  Chico-Martinez  contact,  it  is  quite  likely  that  he  did  not 
distinguish  the  difference  and  so  placed  T.  hoffmaniana  with  the  Chico 


32  Gabb,  Wm.,  Geological  Survey  of  California,  Palaeontology,  vol.  2,  p.  182. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        139 

form,  Pugnellus  hamulus.  Comparing  the  true  Tellina  hoffmaniana, 
i.e.,  the  Chico  form  obtained  from  Pence's  Ranch,  and  described  in  the 
first  volume  issued  by  the  State  Survey,  with  Tellina  kewiTursp.,  the 
following  differences  are  noted :  ( 1 )  The  beaks  of  T.  kewi  are  situated 
anteriorly,  while  those  of  T.  hoffmaniana  are  central.  (2)  The  length 
of  T.  hoffmaniana  is  proportionally  greater  than  T.  kewi.  (3)  The 
posterior  end  of  T.  kewi  is  pointed,  while  that  of  the  other  is  sub- 
truncated.  (4)  The  anterior  end  of  T.  kewi  is  far  more  broadly 
rounded.  Dr.  Stanton  probably  compared  his  specimens  obtained 
from  Lake  County  with  Gabb's  second  figure,  and  hence  identified  it 
as  T.  hoffmaniana. 

Dimensions. — Length,  18  mm. ;  height,  14  mm. ;  convexity,  1 :5  mm. 

Occurrence. — This  Tellina  is  common  at  University  of  California 
localities  784  and  790,  near  Lower  Lake,  Lake  County,  California. 

Named  in  honor  of  Mr.  Wm.  Kew,  University  of  California,  who 
has  ably  assisted  the  writer  in  collecting. 

PSAMMOBIA(f)  CYLINDRICA,  n.  sp. 
Plate  12,  figures  2a,  2& 

Shell  moderately  long,  thick,  convex;  beak  located  a  fifth  of  dis- 
tance from  anterior  end,  prosogyrate,  approximate;  nymph  narrow, 
cylindrical,  elongate;  posterior  dorsal  margin  straight  and  nearly 
parallel  with  the  nearly  straight  ventral  margin ;  anterior  dorsal  mar- 
gin slightly  concave  under  beak,  with  moderate  slope  to  a  narrowly 
rounded  anterior  end;  posterior  end  almost  straight.  A  rounded 
umbonal  slope  extends  from  the  beak  to  the  angle  which  the  posterior 
end  makes  with  the  ventral  margin.  Shell  ornamented  by  concentric 
lines  of  growth. 

Dimensions. — Length,  39  mm. ;  height,  18  mm. ;  convexity,  8  mm. 

Occurrence. — University  of  California  Locality  780,  near  Lower 
Lake  village,  in  the  uppermost  Martinez.  This  locality  is  probably 
200  feet  below  the  base  of  the  Tejon.  It  is  also  found  at  the  very 
top  of  the  Martinez,  at  the  type  locality. 

SP1SULA(?)  WEAVERI,  n.  sp.  Packard 
Plate  12,  figures  4o,  4& 

Shell  small,  relatively  thick,  subtrigonal  to  oval,  moderately  ven- 
tricose,  evenly  rounded;  umbones  nearly  central,  prosogyrate,  promi- 
nent, nearly  adjacent;  anterior  dorsal  margin  concave  for  a  distance 


140  University  of  California  Publications  in  Geology          [VOL.  8 

equal  to  about  one-third  the  height  of  the  shell;  anterior  extremity 
slightly  attenuated,  evenly  rounded;  base  broadly  rounded;  posterior 
evenly  rounded,  curving  gently  in  the  dorsal  region  to  the  beak ;  sur- 
face roughened  by  coarse  lines  of  growth;  hinge  and  interior  but 
imperfectly  known. 

Dimensions. — Length,  32  mm. ;  height,  26  mm. ;  diameter  of  one 
valve,  5mm. 

Horizon. — Lower  Martinez,  Meretrix  dalli  zone. 

This  form  varies  considerably  from  the  type  specimen  to  an  elon- 
gated form,  which  is  slightly  more  ventricose.  Gradational  types  are 
found  between  these  forms. 

Type  from  University  of  California  Locality  1556. 


MARTESIA(?),  sp. 

Shell  elongate  with  thin  test;  beaks  anterior,  incurved,  approxi- 
mate ;  posterior  dorsal  margin  concave  and  undulating ;  anterior  dorsal 
margin  short,  rounded;  anterior  end  rounded;  posterior  end  slightly 
flaring;  ventral  margin  nearly  straight.  One  beaded  umbonal  groove 
diverges  from  the  beak.  A  posterior  groove,  which  indicates  the  position 
of  an  internal  rib,  makes  a  very  obtuse  angle  with  the  ventral  margin. 
Tube  unknown. 

Dimensions. — Height,  13  mm. ;  length,  unknown. 

Occurrence. — Found  at  University  of  California  Locality  784,  near 
Lower  Lake. 

The  posterior  dorsal  margin  is  concave,  while  that  of  Turnus  plenus 
Gabb  of  the  Chico  is  nearly  straight.  Its  flaring  posterior  end  serves 
to  distinguish  it  from  T.  plenus  Gabb  and  Martesia  clausa  Gabb. 

Mr.  Barrows,  who  is  making  a  study  of  boring  molluscs,  kindly 
helped  me  in  determining  this  form. 


GASTROPODA 

ACMAEA  MARTINEZENS1S,  n.  sp. 
Plate  12,  figure  8 

Shell  large,  high,  elliptical,  smooth  except  for  indistinct  growth 
lines;  apex  rounded  and  situated  two-fifths  of  length  from  anterior 
end ;  the  slopes  on  the  sides  from  the  apex  are  much  steeper  than  those 
to  the  ends. 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        141 

Dimensions. — Major  axis,  35  mm. ;  minor  axis,  23  mm. ;  height, 
11  mm. 

Occurrence. — University  of  California  Locality  790. 

This  species  differs  from  A.  tejonensis  Gabb  of  the  Tejon  in  having 
a  rounded  apex  instead  of  a  pointed  curved  one,  and  in  shape  of  base. 

Named  for  the  Martinez  group,  in  which  it  was  found. 

FISSUEELLA(f)  BEHE1,  n.  sp. 
Plate  12,  figure  9 

Shell  oval,  conical,  with  form  and  decoration  like  an  individual 
coral ;  apex  acute,  with  round  aperture  ( ? ) ,  located  two-fifths  of  length 
from  anterior  end;  margin  crenulated;  surface  of  shell  marked  by 
fourteen  acute,  nearly  straight,  radiating  ribs  with  concave  interspaces 
twice  their  width. 

Dimensions. — Major  axis,  12  mm.;  minor  axis,  10  mm.;  height, 
7  mm. 

Occurrence. — University  of  California  Location  243,  Trochocyathus 
zitteli  zone,  type  locality  of  Martinez  Group. 

Named  in  honor  of  Mr.  Ernest  Behr. 

NERITA(?)  BIANGULATA,  n.  sp. 
Plate  12,  figure  12 

Shell  semiglobose,  with  low  immersed  spire,  whorls  three.  The 
body  whorl  is  marked  by  spiral  lines  and  transverse  nodose  ribs.  The 
other  whorls  are  also  nodose.  Mouth  subquadrate.  The  shell  is  marked 
by  two  angles — a  right  angle  setting  off  the  body  whorl  from  the  spire 
and  an  obtuse  angle  which  divides  the  body  whorl  in  halves,  both  of 
which  are  flattened.  Inner  lip  callused  with  plications;  outer  lip 
characters  unknown. 

Dimensions. — Height,  10  mm. ;  width  of  body  whorl,  6  mm. 

Occurrence. — University  of  California  localities  243  and  211. 

This  species  is  easily  distinguished  from  N.  triangulata  Gabb  by  its 
having  only  two  angulations  and  by  the  presence  of  transverse,  nodose 
ribs. 

NATICA  (GYRODES)  LINE  AT  A,  n.  sp. 

Plate  13,  figure  3a,  36 

Shell  of  moderate  size,  solid,  thick,  moderately  elevated,  and  marked 
by  strong  spiral  lines.  These  spiral  lines  are  crossed  by  growth  lines 
occasionally ;  five  rounded  whorls  which  are  distinctly  channeled ;  body 


142  University  of  California  Publications  in  Geology          [VOL.  8 

whorl  large ;  mouth  ovate ;  outer  lip  simple ;  inner  lip  smooth ;  umbilicus 
open  and  appears  to  be  bounded  by  a  line. 

Dimensions. — Height,  18  mm. ;  width  of  body  whorl,  21  mm. 

Occurrence. — This  species  is  abundant  in  the  basal  beds  of  the  Mar- 
tinez, University  of  California  Locality  1556,  from  which  the  type  and 
co-type  were  obtained.  It  ranges  from  the  basal  beds  to  uppermost 
Martinez. 

This  species  is  readily  distinguished  by  its  prominent  spiral  lines 
from  all  other  similar  forms  in  the  Eocene,  except  Bullinula  subglobosa 
Weaver.  It  differs  from  Bullinula  subglobosa  Weaver  by  having  a 
much  wider  aperture,  by  its  distinct  channeling  between  whorls,  and 
by  a  less  prominent  spire. 

AMAUKOPSIS  MARTINEZENSIS,  n.  sp. 
Plate  13,  figures  4o,  46 

Shell  elongated  with  very  high  spire  for  this  genus;  whorls  six; 
rounded  on  sides;  suture  deeply  channeled  and  bordered  by  a  narrow 
flat  margin  which  slopes  to  the  suture.  Aperture  half  oval;  outer  lip 
simple ;  inner  lip  thinly  incrusted  forming  a  fold  which  at  first  sight 
seems  to  be  an  umbilicus.  Surface  marked  by  fine  but  well-marked 
revolving  lines  and  lines  of  growth. 

Dimensions. — Height,  33  mm. ;  width  of  body  whorl,  28  mm. 

Occurrence. — Martinez  Group,  University  of  California  Locality 
1540,  one  mile  south  of  Stewartville. 

This  species  appears  to  be  the  precursor  of  Amauropsis  alveata 
(Conrad).  It  has  a  narrow  channeling  on  upper  portion  of  whorl 
while  A.  alveata  has  a  wide  slightly  concave  channeling.  The  spire 
of  this  species  is  decidedly  higher  than  that  of  A.  alveata.  It  differs 
from  A.  oviformis  Gabb  in  its  greater  height  and  in  its  decoration. 

TUKITELLA  CLAEKI,  n.  sp. 

Plate  13,  figure  8 

Shell  short,  conical  with  eleven  whorls.  When  uneroded  the  whorls 
lines  with  flatly  channeled  interspaces  equal  in  width  to  ribs.  The 
are  nearly  flat.  A  faint  angulation  can  be  seen  slightly  below  the 
center  of  certain  whorls.  This  angle  is  marked  by  a  spiral  line  which 
is  somewhat  stronger  than  the  rest.  The  body  whorl  appears  to  have 
a  double  angulation,  the  spiral  line  below  its  impressed  linear  suture 
marking  the  upper  angle.  The  decoration  consists  of  flat-topped  spiral 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        143 

number  of  spiral  lines  on  the  different  body  whorls  is  variable.  Eight 
were  counted  on  the  penultimate  whorl,  ten  on  the  next  and  seven  on 
the  eighth.  Faint  lines  of  growth  cross  the  spiral  lines. 

Dimensions. — Length,  32  mm. ;  width  of  body  whorl,  12  mm. 

Occurrence. — University  of  California  Locality  1540,  Trocho- 
cyathus  zitteli  zone  north  of  Mount  Diablo. 

This  species  resembles  T.  martinezensis  Gabb  in  its  apical  angle, 
but  the  number  of  spiral  lines  is  much  greater  than  that  of  T.  mar- 
tinezensis. Its  great  apical  angle  is  quite  sufficient  to  distinguish 
this  form  from  all  the  other  Eocene  species  of  this  genus. 

Named  in  honor  of  Mr.  Bruce  L.  Clark,  Instructor  in  Palaeon- 
tology, University  of  California. 

CEEITHIUM,  sp. 
Plate  14,  figure  2 

Shell  robust,  conical,  with  a  large  apical  angle;  about  twelve  flat- 
sided  whorls.  These  whorls  are  decorated  by  about  twenty  vertical 
ribs,  crossed  by  about  ten  revolving  ribs.  Of  the  two  sets,  the  vertical 
is  the  stronger.  The  body  whorl  has  the  short  canal  of  this  genus. 

Dimensions. — Length  of  broken  specimen,  30  mm. ;  width  of  body 
whorl  about  12  mm. 

Occurrence. — Abundant,  but  poorly  preserved  in  the  Martinez  of 
San  Pedro  Point,  San  Mateo  County,  California,  University  of  Cali- 
fornia Locality  692. 

ALAEIA,  sp. 
Plate  14,  figure  3 

Shell  elongated;  spire  high;  nine  or  ten  whorls;  upper  whorls 
spinous,  convex,  widest  a  little  below  the  middle;  last  whorl  sharply 
and  acutely  angulated,  sloping  and  gently  concave  above  and  below 
the  angle ;  suture  impressed.  Surface  ornamented  by  fine,  thread-like, 
revolving  lines,  and  by  sinuous  lines  of  growth.  Canal  long,  narrow, 
straight.  Outer  lip  unicarinate,  slightly  curved. 

Dimensions. — Width  of  body  whorl,  11  mm. ;  approximate  height 
of  spire,  12  mm. 

Occurrence. — University  of  California  Locality  692. 

This  species  resembles  Anchura  angulata  Gabb  closely  and  it  may 
be  identical  with  it,  as  Gabb's  description  was  based  upon  a  single 
poorly  preserved  specimen  found  at  Bull's  Head  Point.  This  form 
may  later  be  found  to  belong  to  the  genus  Spinigera. 


144  University  of  California  Publications  in  Geology          [V°L.  8 

ANCHURA  ENGLISHI,  n.  sp. 
Plate  14,  figure  5 

Shell  fusiform  with  very  low  spire;  six  whorls;  body  whorl  large 
with  long,  slender,  slightly  curved  canal;  lip  long,  straight.  Body 
whorl  shows  a  node  about  ninety  degrees  from  expanded  lip.  The 
portion  of  the  body  whorl  above  the  shoulder  slopes  gently  upward  to 
an  impressed  suture;  decoration,  unknown. 

Dimensions. — Height,  20  mm. ;  width  of  body  whorl,  13  mm. ;  length 
of  expanded  lip,  8  mm. 

Occurrence. — University  of  California  Locality  243,  Trochocyathus 
zitteli  zone  at  type  locality. 

Named  in  honor  of  Mr.  Walter  English. 

ANCHUEA  GABBI,  n.  sp. 
Plate  14,  figure  4 

Shell  small,  fusiform,  spire  elevated,  six  rounded  whorls,  suture 
deep.  Surface  of  upper  whorls  strongly  cancellated  by  transverse 
ribs  and  faintly  revolving  lines;  body  whorl  strongly  marked  by 
two  carinae,  the  upper  one  of  which  extends  outward  to  the  tip  of  the 
lip.  Lip  long  straight  perpendicular  to  whorls,  tip  acute;  canal 
narrow,  length  unknown. 

Dimensions. — Width  of  body  whorl,  6  mm.,  including  lip,  11.5  mm. ; 
length  of  whorls,  13  mm. 

Occurrence. — Martinez  Group,  one  mile  south  of  Stewartville ; 
University  of  California  Locality  1540. 

The  specimen  figured  occurs  in  hard,  gray-green,  glauconitic  sand- 
stone typical  of  the  Martinez  Group.  It  is  associated  with  Tellina 
undulifera,  Cucullaea  mathewsonii,  Tapes(f)  quadrata,  Turritella 
infragranulata,  Perissolax  tricarnatus,  and  Trochocyathus  zitteli, 
characteristic  Martinez  species. 

It  differs  from  A.  transversa  Gabb  in  having  a  shorter  uncurved 
lip  and  its  body  whorl  is  marked  by  two  carinae  instead  of  the  one  as 
in  A.  transversa. 

SERAPHS(?)  THOMPSONI,  n.  sp. 

Plate  14,  figures  6a,  6b 

Shell  elongate,  narrow,  with  spire  almost  as  long  as  body  whorl. 
Seven  whorls  rounded,  cylindrical.  Body  whorl  is  decorated  by  fine 
spiral  lines  crossed  by  lines  of  growth.  Mouth  narrow,  long;  outer 
lip  simple;  inner  lip  slightly  incrusted. 


1914]       Dicker  son:  Fauna  of  the  Martinez  Eocene  of  California        145 

Dimensions. — Length,  20  mm. ;  width  of  body  whorl,  6  mm. 

Occurrence. — University  of  California  Locality  784,  near  Lower 
Lake. 

Named  in  honor  of  Mr.  Percy  W.  Thomson,  Geologist,  Standard  Oil 
Company. 


OVULA  MARTINI,  n.  sp. 
Plate  14,  figures  la,  7b 

Shell  ovoid,  widest  about  one-third  of  the  distance  from  the  upper 
end,  suddenly  narrowing  below;  under  surface  flattened.  Mouth 
straight,  medium  width.  Outer  lip  broad  and  rounded.  Canal  un- 
usually long  for  this  genus. 

Dimensions. — Greatest  width,  28  mm. ;  length,  42  mm. 

Occurrence. — Martinez  Group,  University  of  California  Locality 
243,  and  two  and  one-half  miles  south  of  Muir  Station,  and  one-half 
mile  east  of  the  road  which  crosses  the  Briones  Hills  going  south  from 
Muir  Station,  on  north  slope  of  a  small  tributary  of  a  tributary  of 
Arroyo  del  Hambre,  elevation  550  feet,  100  yards  north  of  Monterey- 
Martinez  contact. 

This  form  differs  from  Cypraea  bayerquei  Gabb  in  that  its  canal  is 
much  longer,  it  is  much  thicker  and  its  shape  is  different. 


TEITONIUM(?)  BUWALDI,  n.  sp. 
Plate  15,  figure  3 

Shell  fusiform,  robust;  spire  probably  high;  number  of  whorls 
unknown,  the  spire  being  defective.  Surface  of  body  whorl  orna- 
mented by  about  fourteen  moderately  long  nodose  longitudinal  ribs  at 
thickest  part  of  whorl.  These  ribs  are  parallel  with  the  axis.  They 
do  not  extend  to  the  impressed  suture  above.  Slightly  below  the 
middle  the  body  whorl  is  decorated  by  eight  prominent  spiral  ribs  with 
interspaces  twice  as  wide.  Mouth  oval ;  inner  lip  slightly  incrusted(  ?)  ; 
outer  lip,  defective ;  canal  long,  slightly  curved. 

Dimensions. — Length  of  broken  specimen,  37  mm. ;  width  of  body 
whorl,  25  mm. 

Occurrence. — Only  one  specimen  of  this  species  was  found,  at 
University  of  California  Locality  790,  near  Lower  Lake. 

Named  in  honor  of  Mr.  J.  P.  Buwalda. 


146  University  of  California  Publications  in  Geology          [VOL.  8 

TEITONIUM  MAKTINEZENSIS,  n.  sp. 
Plate  15,  figure  2 

Shell  fusiform,  turreted,  spire  high  and  nearly  equal  in  length  to 
mouth;  whorls  six;  suture  impressed.  Mouth  wide  above,  narrowed 
in  advance,  canal  slightly  curved.  Surface  marked  by  prominent 
nodes  on  the  angles  of  the  whorls,  prolonged  markedly  below,  but  not 
above.  Well-marked  spiral  lines  of  uniform  size  cover  both  the  nodes 
and  surface  of  the  shell. 

Dimensions. — Height  of  shell,  20  mm. ;  height  of  spire,  7  mm. ; 
width  of  body  whorl,  7  mm. 

Occurrence. — University  of  California  Locality  1556. 

This  Tritonium  resembles  T.  whitneyi  Gabb  in  some  respects.  The 
drawings  of  T.  whitneyi  (Palaeontology  of  California,  vol.  1,  plate  28, 
figs.  210  and  210a)  are  strikingly  like  this  shell,  but  the  type  specimen 
of  T.  whitneyi  differs  in  the  following  ways :  (1)  T.  whitneyi  has  seven 
or  eight  whorls;  (2)  its  nodes  are  only  ''prolonged  slightly  below  and 
above" ;  and  (3)  its  revolving  lines  alternate  in  size  and  divide  the 
nodes  into  two  parts. 

HEMIFUSUS(?)  WARINGI,  n.  sp. 
Plate  15,  figure  10 

Shell  fusiform,  with  short  spire ;  number  of  whorls  unknown ;  body 
whorl  biangular,  with  about  fifteen  axial  ribs  which  become  nodose  at 
the  angles.  One  of  the  angles  is  situated  at  the  middle  of  the  outer 
lip,  while  the  other  is  slightly  below  the  suture.  The  suture  is 
enveloped  by  the  preceding  whorl.  Outer  lip  simple;  columella  in- 
crusted.  Canal  moderately  long  and  nearly  straight.  Five  rounded, 
spiral  lines  ornament  the  body  whorl. 

•     Dimensions. — Height  of  broken  specimen,  28  mm. ;  width  of  body 
whorl,  22  mm. 

Occurrence. — The  species  was  found  in  the  upper  ( ? )  Martinez 
along  the  Santa  Fe  Railroad,  about  two  miles  east  of  Martinez.  It  is 
doubtfully  referred  to  Hemifusus.  When  better  specimens  are  found 
it  may  be  placed  in  the  genus  Clavella. 

Named  in  honor  of  Mr.  C.  A.  Waring. 

FUSUS  DUMBLEI,  n.  sp. 

Plate  16,  figure  6 

Shell  fusiform,  whorls  nine,  angular.  Spire  about  half  length  of 
shell.  Angulation  is  central  on  whorls.  Space  above  and  below  angles 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        147 

is  flat  or  slightly  convex.  Surface  of  body  whorl  marked  by  ten  to 
twelve  spiral  lines  with  interspaces  twice  as  wide;  oblique  lines  of 
growth  are  found  also.  Canal  slender,  very  long,  straight^ 

Dimensions. — Length  of  spire,  12  mm. ;  length  of  body  whorl  from 
suture  to  constriction,  7  mm. ;  width  of  body  whorl,  8  mm. 

Occurrence. — The  type  specimen  was  found  by  Dr.  C.  E.  Weaver 
at  University  of  California  Locality  790,  Lower  Lake. 

Fusus  dumblei  resembles  F.  mathewsonii  Gabb  in  its  marked  angu- 
lation,  but  it  lacks  the  double  angulation  on  the  lower  whorls  and  it 
is  far  less  robust  than  F.  mathewsonii.  This  is  the  only  Fusus  thus 
far  reported  from  the  Martinez  of  Lower  Lake. 

Named  in  honor  of  Professor  E.  T.  Dumble,  Consulting  Geologist, 
Southern  Pacific  Company. 


OLIVELLA  CLAYTONENSIS,  n.  sp. 

Plate  16,  figure  7 

Small,  spire  very  low ;  whorls  four,  suture  covered ;  surface  marked 
faintly  by  transverse  growth  lines,  mouth  not  exposed.  Outer  lip 
thickened. 

Dimensions. — Height,  8  mm. ;  width  of  body  whorl,  4  mm. 

Occurrence. — University  of  California  Locality  1543. 

This  species  differs  from  Olivella  mathewsonii  in  height  of  spire. 


TUEEIS  LOUDERBACKI,  n.  sp. 
Plate  16,  figures  9a,  9& 

Shell  fusiform,  with  high  spire  which  is  nearly  equal  in  length  to 
the  body  whorl;  eight  whorls  marked  by  twelve  rounded  nodes.  The 
slightly  concave  space  above  the  shoulder  of  the  whorl  slopes  steeply 
from  the  impressed  linear  suture.  In  the  whorls  of  the  spire  this 
space  is  twice  as  lorg  as  the  nodose  convex  space  below  the  angle. 
Fine  rounded  spiral  lines  decorate  the  whorls.  Growth  lines  indicate 
a  sinus  at  angle.  Outer  lip  simple;  inner  lip  incrusted;  canal  long, 
straight. 

Dimensions. — Length  of  nearly  complete  specimen,  35  mm. ;  width 
of  body  whorl,  13  mm. 

Occurrence. — University  of  California  Locality  1540,  Trocho- 
cyathus  zitteli  zone  north  of  Mount  Diablo,  and  same  zone  at  type 
locality. 


148  University  of  California  Publications  in  Geology          [VOL.  8 

Its  very  graceful,  long,  turreted  spire  is  its  distinguishing  feature. 
Named  in  honor  of  Professor  Gr.  D.  Louderback,  University  of 
California. 

SURCULA  MEBBIAMI,  n.  sp. 
Plate  16,  figure  10 

Shell  fusiform,  with  moderately  high  spire,  with  seven  or  more 
nodose  whorls ;  suture  line  prominent  and  just  below  the  nodes.  About 
fourteen  nodes  ornament  the  body  whorl,  while  only  ten  are  found  on 
the  fourth  whorl.  The  nodes  are  acute,  and  strong  spiral  lines  mark 
them.  The  nodes  on  the  body  whorl  are  much  longer  than  those  on 
the  upper  whorls.  The  portion  of  the  whorl  between  the  shoulder  and 
the  suture  is  concave  with  the  center  of  the  concavity  two-thirds  of 
the  total  distance  above  the  nodes.  This  surface  is  marked  by  the 
curved  lines  of  growth  of  the  sinus,  and  the  apex  of  the  curve  is  two- 
thirds  the  distance  above  the  nodes,  thus  indicating  the  position  of  the 
sinus.  The  canal  is  broken  but  the  upper  portion  suggests  that  it  is 
a  long  one. 

Dimensions. — Length  of  broken  specimen,  21  mm. ;  width  of  body 
whorl,  13  mm. 

Occurrence. — University  of  California  localities  1556  and  1558. 

The  strong  spiral  lines  on  the  nodes  are  the  distinctive  features  of 
this  shell.  Two  specimens  have  been  found. 

Named  in  honor  of  Professor  J.  C.  Merriam. 


SUBCULA  FAIBBANKSI,  n.  sp. 
Plate  16,  figure  12 

Shell  spindle-shaped,  slender  with  eight  whorls,  nodose,  convex  and 
angulated  in  middle ;  suture  well  marked  and  deep.  About  ten  nodes 
ornament  each  whorl.  They  extend  to  the  suture.  The  whorls  are 
but  slightly  swollen.  The  portion  of  the  whorl  between  the  shoulder 
and  the  surface  is  flat  and  the  lines  of  growth  of  this  area  are  curved 
with  the  apex  of  the  curve  near  the  suture,  indicating  that  the  sinus 
is  above  the  shoulder  of  the  whorl.  The  inner  lip  appears  to  be 
slightly  incrusted. 

Dimensions. — Length,  45  mm. ;  width  of  body  whorl,  20  mm. 

Occurrence. — University  of  California  Locality  1540. 

At  first  sight  this  shell  looks  like  Pleurotoma  fresnoensis  Arnold, 
but  it  is  much  larger,  the  number  of  whorls  is  only  eight  instead  of 


1914]       Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        149 

ten  of  the  P.  fresnoensis,  and  its  apical  angle  is  decidedly  greater. 
The  nodes  of  this  shell  are  not  so  pointed  as  those  of  8.  crenatospira 
Cooper.  The  portion  of  the  whorl  between  the  shoulder  and  the 
suture  in  8.  crenatospira  is  curved. 

Named  in  honor  of  Dr.  H.  W.  Fairbanks. 


SUECULA  (SUKCULITES)  ANDEESONI,  n.  sp. 
Plate  16,  figure  11 

Shell  very  long,  slender ;  spire  high  about  two-fifths  of  length ;  nine 
or  ten  whorls,  nodose,  angulated,  with  sinus  slightly  above  angle  judg- 
ing from  growth  lines ;  twelve  or  thirteen  elongate  rounded  nodes  mark 
each  whorl.  The  body  whorl  is  distinctly  marked  by  revolving  lines 
which  alternate  in  size.  A  very  distinct  collar  appears  just  below  the 
channeled  suture  of  each  whorl. 

Dimensions. — Length  of  broken  specimen,  40  mm. ;  width  of  body 
whorl,  12  mm. 

Occurrence. — The  type  specimen  was  found  at  University  of  Cali- 
fornia Locality  243,  Trochocyathus  zitteli  zone  of  type  locality.  It 
also  occurs  at  Selby  Smelter  on  the  Carquinez  Straits. 

Surcula  (Surculites)  praeattenuata  Gabb  of  the  Tejon  resembles 
this  species  closely,  but  its  body  whorl  is  decidedly  shorter  in  propor- 
tion to  length. 

Named  in  honor  of  Mr.  F.  M.  Anderson,  Curator  of  Invertebrate 
Palaeontology,  California  Academy  of  Sciences,  San  Francisco. 


SUECULA,  sp. 
Plate  16,  figures  13o,  136 

Shell  fusiform,  with  moderately  high  spire,  with  seven  or  more 
nodose  whorls;  suture  line  prominent  and  just  beneath  the  nodes. 
About  fourteen  nodes  ornament  the  body  whorl,  while  only  ten  are 
found  on  the  fourth  whorl.  The  nodes  are  acute,  and  strong  spiral 
lines  of  growth  mark  them.  The  nodes  on  the  body  whorl  are  much 
longer  than  those  on  the  upper  whorls.  The  portion  of  the  whorl 
between  the  shoulder  and  the  suture  is  concave,  with  the  center  of 
the  concavity  two-thirds  of  the  total  distance  above  the  nodes.  This 
surface  is  marked  by  the  curved  lines  of  growth  of  the  sinus  and  the 
apex  of  the  curve  is  two-thirds  the  distance  above  the  nodes,  thus 


150  University  of  California  Publications  in  Geology          [VOL.  8 

indicating  the  position  of  the  sinus.     The  canal  is  broken,  but  the 
upper  portion  suggests  that  it  is  a  long  one. 

Dimensions. — Width  of  body  whorl,  13  mm. 

Occurrence. — University  of  California  Locality  1540. 


CEPHALOPODA 

HEECOGLOSSA  MERRIAMI,  n.  sp. 
Plate  17,  figures  5a,  56 

Shell  medium  in  size,  aperture  wide;  ventral  saddles  large  and 
simple;  lateral  lobes  well  rounded,  becoming  more  acute  toward  the 
posterior;  lateral  saddles  well  rounded  but  not  so  acute  as  the  lateral 
lobes. 

Dimensions. — Diameter  about  90  mm. 

Occurrence. — Two  specimens  have  been  found  at  University  of 
California  Locality  243,  Trochocyathus  zitteli  zone,  type  locality  of 
the  Martinez. 

This  species  differs  from  H.  tuomei  Clark  and  Martin  and  from 
H.  ulrichi  (White)  in  its  more  acute  lateral  lobes  and  saddles.  Its 
aperture  is  narrower  than  that  of  E.  ulrichi.  In  other  respects  it 
resembles  this  last  mentioned  species  closely. 


NAUTILUS  STEPHENSONI,  n.  sp. 
Plate  18,  figures  2a,  2& 

Shell  subglobose.  Whorls  increasing  very  rapidly  in  size.  The 
body  whorl  is  large,  convex,  rounded  on  sides;  the  other  whorls  are 
immersed  in  it.  Umbilicus  covered.  Surface  decorated  by  very  fine 
sinuous  lines  of  growth.  Septa  slightly  undulating;  ventral  lobe 
slightly  concave;  the  lateral  lobe  and  lateral  saddle  gently  curved. 
The  uniform  rounding  of  the  body  whorl  is  a  very  pronounced  feature 
of  this  species. 

Dimensions. — Greatest  diameter  32  mm. 

Occurrence. — University  of  California  Locality  243. 

This  species  is  decidedly  more  globose  than  the  species  described 
by  Gabb  as  Nautilus  texanus(f)  Shumard. 

Named  in  honor  of  the  collector,  Dr.  L.  W.  Stephenson,  Acting 
Professor  of  Palaeontology,  University  of  California. 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        151 


PEEVIOUSLY  DESCEIBED  MARTINEZ   SPECIES  RE-FIGURED 

Several  of  the  better  preserved  and  characteristic  species  of  the 
Martinez  fauna  have  been  figured  in  this  paper  in  order  that  the 
reader  might  have  comparative  forms  before  him.  They  are  as  follows : 

Flabellum  remondianum  Gabb.    Plate  6,  figures  la,  15,  Ic,  Id. 

Trochocyathus  zitteli  (Merriam).    Plate  6,  figures  3a,  35,  3c,  3d. 

Schizaster  lecontei  Merriam.    Plate  6,  figure  7. 

Terebratulina  tejonensis  Stanton.    Plate  7,  figures  2a,  25. 

Cucullaea  mathewsonii  Gabb.    Plate  7,  figures  la,  75,  8. 

Lima  multiradiata  Gabb.    Plate  8,  figure  1. 

Phalodomya  nasuta  Gabb.    Plate  9,  figures  la,  16. 

Psammobia  hornii  (Gabb).    Plate  11,  figure  10. 

Mytilus  cf.  ascia  Gabb.    Plate  9,  figure  2. 

Pecten  interradiatus  Gabb.    Plate  9,  figure  5. 

Modiolus  merriami  (Weaver).    Plate  9,  figure  7. 

Cuspidaria  dolabraeformis  (Gabb),  Plate  9,  figure  9. 

Plicatula  ostreaformis  Stanton.    Plate  9,  figure  12. 

Crassatellites  unioides  (Stanton).     Plate  10,  figure  2. 

Glycimeris  veatchii  var.  major  (Stanton).    Plate  10,  figure  5. 

Phacoides  turneri  (Stanton).    Plate  10,  figure  8. 

Tapes  (?)  quadrata  Gabb.    Plate  11,  figure  5. 

Tellina  undulifera  Gabb.    Plate  11,  figures  la,  75,  Ic. 

Tellina  cf.  parilis  Gabb.    Plate  11,  figure  12. 

Solen  stantoni  Weaver.    Plate  12,  figure  3. 

Mactra(?)  tenuissima  Gabb.    Plate  12,  figure  5. 

Dentalium  cooperi  Gabb.    Plate  12,  figure  7. 

Discohelix  californicus  Weaver.    Plate  12,  figure  10. 

Architectonica  tuberculata  Weaver.    Plate  13,  figures  2a,  25. 

Lunatia  hornii  Gabb.    Plate  13,  figure  5. 

Lunatia  cf.  nuciformis  Gabb.    Plate  13,  figures  6a,  65. 

Xenophora  zitteli  Weaver.    Plate  13,  figure  7. 

Turritella  infragranulata  Gabb.    Plate  13,  figures  9a,  95. 

Turritella  martinezensis  Gabb.    Plate  13,  figure  10. 

Turritella  pachecoensis  Stanton.    Plate  14,  figures  la,  15,  Ic. 

Cypraea  bayerquei  Gabb.    Plate  15,  figure  1. 

Brachysphingus  liratus  Gabb.    Plate  15,  figure  4. 

Turbinella  crassatesta  Gabb.    Plate  15,  figure  5. 

Urosyca  caudata  Gabb.    Plate  15,  figures  la,  75. 

Urosyca  robusta  Gabb.    Plate  15,  figure  8. 

Siphonalia(?)  lineata  Stanton.    Plate  15,  figure  9. 

Neptunea  mucronata  Gabb.    Plate  15,  figure  11. 

Neptunea  cretacea  Gabb.    Plate  15,  figure  12. 

Fusus  aequilateralis  Weaver.    Plate  16,  figure  1. 

Fusus  mathewsonii  Gabb.    Plate  16,  figure  2. 

Fusus  occidentalis  Gabb.    Plate  16,  figure  3. 

Fusus  aratus  Gabb.    Plate  16,  figure  4. 

Fusus  flexuosus  Gabb.    Plate  16,  figure  5. 

Perissolax  tricarnatus  Weaver.    Plate  16,  figures  8a,  85. 

Heteroterma  gabbi  Stanton.    Plate  17,  figure  1. 


152  University  of  California  Publications  in  Geology          [VOL.  8 

Actaeon  lawsoni  Weaver.    Platae  17,  figure  2. 
Bullinula  subglobosa  Weaver.    Plate  17,  figure  3. 
Einginella  pinguis  Gabb.    Plate  17,  figures  4o,  4ft. 
Aturia  mathewsonii  Gabb.    Plate  18,  figure  1. 

All  the  species  figured  were  obtained  from  the  Martinez  Group. 
Several  of  Gabb's  genera  are  not  in  accord  with  present  usage,  but 
they  have  been  retained  in  this  paper  in  those  cases  where  the  correct 
genus  was  uncertain. 


APPENDIX 

LIST  OF  LOCALITIES* 

65.  Concord  Quadrangle.  Martinez  Group.  Alhambra  Valley.  On  ridge  just 
east  of  point  where  Arroyo  del  Hambre  turns  to  the  north,  two  and  one- 
quarter  miles  south  of  Muir  Station.  J.  C.  M.  Loc.  65.  Concord  Sheet. 

150.     See  340. 

243.  Concord  Quadrangle.  Martinez  Group.  Same  as  500  and  544.  One  and 
three-fourths  miles  due  south  of  Muir  Station. 

267.  Concord  Quadrangle.  Martinez  Group.  One-sixteenth  mile  north  from 
Arroyo  del  Hambre.  Two  miles  south  30  degrees  west  of  Muir  Station. 
J.  C.  M.  Loc.  267. 

337.  Concord  Quadrangle.  One  and  one-quarter  miles  southeast  of  Muir 
Station.  On  hillside  northeast  side  of  Martinez- Walnut  Creek  road, 
75  feet  above  road.  J.  C.  M.  Loc.  337. 

340.  Mount  Diablo  Quadrangle.  Summer  School,  1911.  Martinez  Group. 
SE  %  of  NE  }4  Sec.  4,  K.  1  W,  T.  1  S,  Mount  Diablo  Sheet. 

333.  Concord  Quadrangle.  Martinez  Group.  Two  and  one-quarter  miles  south, 
10  degrees  west  of  Muir  Station.  J.  C.  M.  Loc.  333. 

500.     Same  as  243  and  544.    See  Loc.  243. 

501  =  213.  Concord  Quadrangle.  Martinez  Group.  Two  and  one-eighth  miles 
southeast  of  Muir  Station  on  the  southwest  side  of  Martinez-Walnut 
Creek  road,  about  one  and  one-half  miles  northwest  of  Grayson's 
Creek,  on  side  of  hill  near  top,  a  little  to  north  of  Locality  343  but  on 
same  hill.  J.  C.  M.  Loc.  501  =  213.  Concord  Sheet. 

532.  Concord  Quadrangle.  Eocene.  One  and  three-eighths  miles  southeast  of 
Muir  Station.  Across  road  from  541,  on  side  of  hill.  J.  C.  M.  Loc.  532. 

541.  Concord  Quadrangle.  On  south  side  of  road  a  little  over  one  and  three- 
eighths  miles  southeast  of  Muir  Station.  J.  C.  M.  Loc.  541.  Concord 
Sheet. 

544.     See  243. 


*  The  initials,  J.  C.  M.  refer  to  the  collections  of  J.  C.  Merriam,  and  R.  E.  D. 
to  those  of  R.  E.  Dickerson. 


1914]      Dickerson:  Fauna  of  the  Martinez  Eocene  of  California        153 

779.  Vicinity    of   Lower   Lake,    Lake    County.      Martinez    Group,    uppermost 

strata.    "SW  %  of  NE  %  of  Sec.  8,  T.  12  N,  E.  6  W,"  Map  88. 

780.  Vicinity  of  Lower  Lake,  Lake  County.    Martinez  Group.    NW  %  of  SW 

%  of  Sec.  36,  T.  13  N,  E.  7  W;  3000  to  3300  feet  (strat.J~ab-ove  Mar- 
tinez base.  Limestone  in  shale. 

782.  Vicinity  of  Lower  Lake,  Lake  County.  Martinez  Group.  SE  }4  of  SE 
^4  of  Sec.  26,  T.  13  N,  E.  7  W,  in  canon  whose  creek  flows  past  old 
dam;  2000  to  2500  feet  (strat.)  above  north  contact  line  of  Chico- 
Martinez.  Map  88. 

784.  Vicinity  of  Lower  Lake,  Lake  County.    Martinez  Group.    NW  }4  of  NE 

%  of  Sec.  11,  T.  12  N,  E.  7  W,  about  one-fourth  to  one-half  mile  east 
and  a  little  south  of  Lower  Lake  on  Knoxville  road,  1000  feet  (hor- 
izontal distance)  above  the  Chico-Martinez  contact,  well  at  old  brick 
yard.  (A  Stanton  locality.)  Map  88. 

785.  Vicinity  of  Lower  Lake,  Lake  County.     Tejon  Group.    NW  %  of  SW  % 

of  Sec.  6,  T.  13  N,  E.  6  W,  in  west  gully  near  hill  top.  Elevation, 
1750  feet.  Map  88. 

787.  Vicinity  of  Lower  Lake,  Lake  County.     Martinez  Group.     SE  *4  of  SE 

%  of  Sec.  36,  T.  13  N,  E.  6  W,  on  south  side  of  Cache  Creek.  Mar- 
tinez Group,  about  300  feet  stratigraphically  below  Martinez-Tejon 
contact.  Map  88. 

788.  Vicinity  of  Lower  Lake,  Lake  County.     Martinez  Group.    SW  ^  of  SW 

%  of  Sec.  1,  T.  13  N,  E.  7  W,  1000  feet  north  of  Herndon  Creek  bridge, 

Knoxville  road.     Map  88. 
790.     Vicinity  of  Lower  Lake,  Lake  County.    Martinez  Group.     SE  %  of  NE 

%  Sec.  11,  T.  12  N,  E.  7  W,  three-fourths  of  a  mile  east  of  Lower  Lake, 

1200  feet  south  from  bridge  over  Herndon  Creek,  in  gully  on  west  side 

of  creek.    Map  88. 
1540.     Mount  Diablo  Quadrangle.     (Loc.  91  E.  E.  D.)     One  mile  south  of  Stewart  - 

ville,  100  yards  south  of  basal  Tejon  conglomerate  and  600  feet  north 

of  Chico-Martinez  contact.     Elevation,  1000  feet.     NE  cor.  of  NW  % 

of  Sec.  15,  E.  1  E,  T.  1  N,  Mount  Diablo  B.  L.  and  M. 
1547.     Concord  Quadrangle.     Seven  and  one-half  miles  south  of  north  edge  of 

Concord  Sheet,  just   south  of  Arroyo  del  Hambre  Creek.     Martinez 

sandstone. 

1556.  Mount  Diablo  Quadrangle.    A  little  over  one  mile  south  of  Stewartville, 

ten  feet  above  the  Martinez-Chico  contact,  in  basal  Martinez  beds. 
Elevation,  1050  feet.  NE  ^4  of  NW  %  of  Sec.  15,  T.  1  N,  E.  1  E, 
Mount  Diablo  B.  L.  and  M. 

1557.  Mount  Diablo  Quadrangle.     Sec.  15  E.  1  E,  T.  1  N.     In  Martinez  near 

Chico  contact.     (Map  61). 

1558.  Mount  Diablo  Quadrangle.     (Loc.  41  E.  E.  D.)     Martinez  Group.     Two 

and  one-fourth  miles  east  of  Clayton.  Elevation,  1450  feet,  200  feet 
stratigraphically  above  the  Martinez-Chico  contact.  SW  ^4  of  Sec.  8, 
T.  1  N,  E.  1  E,  Mount  Diablo  B.  L.  and  M. 

1580.  Mount  Diablo  Quadrangle.  About  one  mile  south  of  Stewartville.  Ele- 
vation, 1000  feet,  400  feet  stratigraphically  above  the  Martinez-Chico 
contact.  The  same  stratum  as  Loc.  1540.  NW  %  of  NE  %  of  Sec.  15, 
T.  1  N,  E.  1  E,  Mount  Diablo  B.  L.  and  M. 


154  University  of  California  Publications  in  Geology          [VOL.  8 

1586.     Mount  Diablo  Quadrangle.    Martinez  Group.    South  part  of  Sec.  8,  E.  1  E, 

T.  1  N,  Mount  Diablo  B.  L.  and  M. 
1592.     Mount  Diablo  Quadrangle.     Martinez   Group.     SW  cor.  Sec.   8,  E  1  E, 

T.  1  N,  Mount  Diablo  B.  L.  and  M. 
1695.     Mount  Diablo  Quadrangle.     Martinez  Group.     On  hilltop  west  of  point 

where  basal  Tejon  conglomerate  crosses  creek.     Sec.  14,  E.  1  E,  T.  1  N, 

Mount  Diablo  B.  L.  and  M. 
1743.     Mount  Diablo  Quadrangle.     Martinez   Group.     One   and   one-half  miles 

south  of  Somerville.    Elevation,  950  feet  and  about  twenty  feet  strati- 

graphically  above  the  Martinez-Chico  contact,  in  the  same  zone  as 

1556.    NE  cor.  of  Sec.  16,  T.  1  N,  E.  1  E,  Mount  Diablo  B.  L.  and  M. 

1745.  Mount  Diablo  Quadrangle.     Martinez   Group.     One  and  one-half  miles 

south  of  Somerville.  Elevation,  900  feet,  seventy-five  feet  strati- 
graphically  above  the  Martinez-Chico  contact.  Sec.  16,  T.  1  N,  E.  1  E, 
Mount  Diablo  B.  L.  and  M. 

1746.  Mount  Diablo  Quadrangle.    (E.  E.  D.  Loc.  506.)    Martinez  Group.    About 

two  and  one-fourth  miles  east  of  Clayton.  Elevation,  1450  feet. 
About  300  feet  stratigraphically  above  the  Martinez-Chico  contact. 
SW  cor.  of  Sec.  8,  T.  1  N,  E.  1  E,  Mount  Diablo  B.  L.  and  M. 

1747.  Mount  Diablo  Quadrangle.     (E.  E.  D.  Loc.  507.)     Martinez  Group.    Four 

miles  due  east  of  Clayton.  Elevation,  900  feet.  About  400  feet  strati- 
graphically above  the  Martinez-Chico  contact  in  the  same  strata  as 
1540.  SE  cor.  of  Sec.  9,  T.  1  N,  E.  1  W,  Mount  Diablo  B.  L.  and  M. 

1828.  Concord  Quadrangle.     Martinez  Group.     On  southwest  side  of  Martinez- 

Walnut  Creek  road  two  and  one-fourth  miles  southeast  of  Muir  Station 
on  hill  slope.  Elevation,  400  feet.  Waud  and  Dickerson. 

1829.  Concord  Quadrangle.    Martinez  Group.     On  southwest  side  of  Martinez- 

Walnut  Creek  road  two  and  three-eighths  miles  southeast  of  Muir 
Station.  Elevation,  475  feet.  Waud  and  Dickerson. 

1830.  Santa  Cruz  Quadrangle.    San  Mateo  County  between  the  head  waters  of 

San  Lorenzo  Eiver  and  Pescadero  Creek.     See  map  47.    Dickerson. 
1888.     Napa  Quadrangle.    Martinez  Group.    On  road  75  feet  above  the  railroad 


EXPLANATION  OF  PLATE  6 
Fauna  of  Martinez  Eocene 

Fig.  la.  Flabellum  remondianum  Gabb.    X  1. 

This  species  ranges  from  the  lowermost  to  the  uppermost  Martinez 
in  the  Mount  Diablo  region  and  the  type  locality.  As  far  as  known  it 
is  restricted  to  the  Martinez  Group.  The  proportions  of  this  species 
are  variable. 

Fig.  1Z>.  Fabellum  remondianum  Gabb,  showing  a  shorter  specimen.     X  1. 

Fig.  Ic.  Flabellum  remondianum  Gabb.     Cross-section  view  after  Vaughan.     X  2. 

Fig.  Id.  Flabellum  remondianum  Gabb.    Bottom  view.     X  1. 

Fig.  2.     Paracyathus( '? ) ,  sp.     XI. 

Fig.  3o.  Trochocyathus  zitteli  (Merriam).     X  1. 

This  individual  coral  is  distinctive  of  the  middle  zone  of  the  Mar- 
tinez and  restricted  to  it.  Its  variations  in  shape  and  size  are  note- 
worthy. 

Fig.  3b.  Trochocyathus  zitteli  (Merriam),  showing  high  specimen.     X  1. 
Fig.  3c.  Trochocyathus  zitteli  (Merriam),  showing  stout  specimen.     X  1. 

Fig.  3d.  Trochocyathus  zitteli    (Merriam).     Cross-section   view  after  Vaughan. 
X  3%. 

Fig.  4o.  Cidaris,  sp.  (a).     X  2. 

Fig.  4b.  Cidaris,  sp.  (a),  distal  end.     X  5. 

Fig.  5.     Cidaris,  sp.  (d).     X  2. 

Fig.  6a.  Cidaris(?),  sp.   (c),  side  view.     X  2. 

Fig.  6b.  Cidaris(?),  sp.  (c),  top  view.     X  2. 

Fig.  7.     Schizaster  lecontei  Merriam.     X  1. 

This  echinoderm  has  an  exceedingly  great  range,  being  found  in 
the  lowermost  Martinez  and  in  the  uppermost  or  Siphonalia  sutterensis 
zone  of  the  Tejon  Group  at  the  Marysville  Buttes. 


[156] 


UNIV.   CALIF.    PUBL.   BULL,    DEPT.   GEOL. 


[DICKERSON]   VOL.   8,    PL.   6 


la 


3a 


6a 


•    :.; 


6b 


Id 


mm. 


lc 


EXPLANATION  OF  PLATE  7 

Fauna  of  Martinez  Eocene 
Fig.  1.     Rhynconellaf?),  sp.     X  3. 

Fig.  2a.  Terebratulina  tejonensis  Stanton.     X  1. 

This  species  occurs  in  the  lowermost  portion  of  the  Martinez  of 
Lake  County  and  of  the  Mount  Diablo  region. 

Fig.  2fe.  Terebratulina  tejonensis  Stanton.     X  1. 

Fig.  3a.  Leda  paclcardi,  n.  sp.     X  2. 

Fig.  3b.  Leda  paclcardi,  n.  sp.     X  2. 

Fig.  4.     Leda  milleri,  n.  sp.     X  2. 

Fig.  5.     Toldia  gesteri,  n.  sp.     XI. 

Fig.  6.     Yoldia(?)  powersi,  n.  sp.     X  3. 

Fig.  la.  Cucullaea  matheivsonii  Gabb,  umbonal  view.     X  3 . 
A  characteristic  Martinez  species. 

Fig.  7b.  Cucullaea  mathewsonii  Gabb,  side  view.     X  1. 

Fig.  8.     Cucullaea  mathewsonii  Gabb  (Area  biloba  Weaver ).     X  3. 

This  figure  is  Weaver's  type  of  Area  biloba  which  is  the  young  of 
C.  mathewsonii.  Small  specimens  have  been  recently  found  which  show 
the  hinge  of  the  genus  Cucullaea. 

Fig.  9a.  Lima(?)  claytonensis,  n.  sp.     X  10. 
Fig.  9b.  Lima( ?)  claytonensis,  n.  sp.     X  10. 


[158] 


UNIV.  CALIF.   PUBL.   BULL.   DEPT.  GEOL. 


[DICKERSON]   VOL.  8,    PL.   7 


7b 


EXPLANATION  OF  PLATE  8 
Fauna  of  Martinez  Eocene 

Fig.  1.     Lima  multiradiata  Gabb.     X  1. 

The  specimen  figured  was  found  at  the  type  locality  of  this  species 
near  Lower  Lake. 

Fig.  2.     Lima  haseltinei,  n.  sp.     X  1. 

This  form  is  the  largest  pelecypod  found  in  the  California  Eocene. 

Fig.  3.     Pinna  barrowsi,  n.  sp.     X  1. 

This  species  also  occurs  in  the  Tejon. 


[160] 


UNIV.   CALIF.    PUBL.    BULL.    DEPT.   GEOL. 


{DICKERSON]    VOL.   8,    PL.   8 


EXPLANATION  OF  PLATE  9 
Fauna  of  Martinez  Eocene 

Fig.    la.  Pholadomya  nasuta  Gabb.     X  1. 

This  species  ranges  throughout  the  Martinez. 

Fig.  16.  Pholadomya  nasuta  Gabb,  umbonal  view.     X  1. 

Fig.  2.     Mytilus  cf.  ascia  Gabb.     X  1. 

Fig.  3.     Ostrea  weaveri,  n.  sp.     X  1. 

Fig.  4.     Ostrea  buwaldana,  n.  sp.     X  1. 

Fig.    5.     Pecten  interradiatus  Gabb.     X  2  . 
Eange,  Martinez  and  Tejon. 

Fig.    6.     Pecten,  sp.     X  2. 

Fig.    7.     Modiolus  merriami  (Weaver).     X  1. 

This  form  is  also  found  in  the  lower  portion  of  the  Tejon  south  of 
Mount  Diablo. 

Fig.    8.  Modiolus  bakeri,  n.  sp.     X 1. 

Fig.    9.  Cuspidaria  dolabraef  ormis  (Gabb).     X  3. 

Fig.  10.  Cuspidaria  hannibali,  n.  sp.     X  2. 

Fig.  11.  Lima(?)  haseltinei,  n.  sp.     X  2. 

Fig.  12.     Plicatula  ostreaf ormis  Stanton.     X  1. 

The  form  figured  is  from  the  type  locality  of  the  species,  near 
Lower  Lake. 


UNIV.   CALIF.    PUBL.    BULL,    DEPT.   GEOL. 


[DICKERSON]    VOL..  8,    PL.   9 


10 


y? 


EXPLANATION  OF  PLATE  10 

Fauna  of  Martinez  Eocene 
Fig.    1.     Crassatellites  studleyi,  n.  sp. 

Fig.    2.     Crassatellites  unioides  (Stanton). 

This  species  has  a  great  geographical  range,  being  found  in  the 
Martinez  of  the  Santa  Ana  Mountains  and  in  the  vicinity  of  Lower 
Lake,  Lake  County,  California. 

Fig.    3.     Crassatellites  stewartvillensis,  n.  sp. 
Fig.    4a.  Crassatellites  claytonensis,  n.  sp.     X  2. 
Fig.    46.  Crassatellites  claytonensis,  n.  sp.     X  2. 

Fig.    5.     Glycimeris  veatchii  var.  major  (Stanton).     XI. 
A  common  form  restricted  to  the  Martinez. 

Fig.    6.  Phacoides  quadrata,  n.  sp.     X  2. 

Fig.    7.  Phacoides  diaboli,  n.  sp.     X  1. 

Fig.    8.  Phacoides  turneri  (Stanton).     X  1. 

Fig.    9.  Dosinia( ?)  lawsoni,  n.  sp.     X  2. 

Fig.  10.  Venus(?),  sp.     XI. 

Fig.  llo.  Phacoides  muirensis,  n.  sp.     X  2. 

Fig.  116.  Phacoides  muirensis,  n.  sp.,  umbonal  view.     X  2. 


[164] 


UNIV.   CALIF.    PUBL.    BULL.    DEPT,    GEOL.  [DICKERSON]    VOL.  8,    PL.    10 


4b 


4a 


8        9 


EXPLANATION  OF  PLATE  11 
Fauna  of  Martinez  Eocene 

Fig.    la.  Meretrix  stantoni,  n.  sp.     X  1. 

A  species  which  occurs  at  nearly  all  localities  of  the  lower  Martinez. 

Fig.    16.  Meretrix  stantoni,  n.  sp.     X  1. 

Fig.    2a.  Meretrix  dalli,  n.  sp.     XI. 

A  species  restricted  to  the  lower  Martinez. 

Fig.    2ft.  Meretrix  dalli,  n.  sp.     X  1. 

Fig.    3.     Meretrix,  sp.     X  1. 

Fig.    4.     Macrocallista( ?)  packi,  n.  sp.     X  1. 

Fig.    5.     Tapes(?)  quadrata  Gabb.     X  1. 
Eange,  Tejon  and  Martinez. 

Fig.    6.     Papliia(?)  clarU,  n.  sp.     X  2. 

Fig.    la.  Tellina  undulifera  Gabb.     X  1. 

An  abundant  and  easily  identifiable  form  which  is  somewhat  vari- 
able in  shape,  as  the  figures  show.     Eange,  throughout  the  Martinez. 

Fig.    7b.  Tellina  undulifera  Gabb.     X  1. 
Fig.    7c.  Tellina  undulifera  Gabb.     X  1. 

Fig.    8.     Tellina  perrini,  n.  sp.     XI. 
Fig.    9.     Tellina  herndonensis,  n.  sp.     X  1. 

Fig.  10.     Psammobia  hornii  (Gabb).     X  1. 

This  Psammobia  has  a  range  throughout  both  the  Martinez  and  Tejon. 

Fig.  11.     Tellina  paclcardi,  n.  sp.     X  1. 
Fig.  12.     Tellina  cf.  parilis  Gabb.     X  3. 


[166] 


UNIV.    CALIF.    PUBL.    BULL,    DEPT.   GEOL. 


[DICKERSON]   VOL.   8,    PL,    II 


lb 


EXPLANATION  OF  PLATE  12 

Fauna  of  Martinez  Eocene 
Fig.    1.     Tellina  kewi,  n.  sp.     X  3. 
Fig.    2a.  Psammobia( ? )  cylindrica,  n.  sp.     X  1. 
Fig.    2b.  Psammobia(?)  cylindrica,  n.  sp.     X  1. 

Fig.    3.     Solen  stantoni  Weaver,  after  Weaver.     X.  1. 

This  species  is  abundant  and  rather  characteristic  of  the  uppermost 
Martinez. 

Fig.  4a.  Spisula(?)  weaveri,  n.  sp.  Packard.     X  1. 

Fig.  4b.  Spisula(?)  weaveri,  n.  sp.  Packard.     X  1. 

Fig.  5.  Mactra(?)  tenuissima  Gabb.     X   2. 

Fig.  6.  Teredo,  sp.    XI. 

Fig.    7.     Dentalium  cooperi  Gabb.     X  1. 

This   smooth,   large   Dentalium   is   found    in    the    Chico-Cretaceous 
Martinez,  and  the  Tejon. 

Fig.    8.  Acmaea  martinezensis,  n.  sp.     X  1. 

Fig.    9.  Fissurella(f)  behri,  n.  sp.     X  2. 

Fig.  10.  Discolielix  calif ornicus  Weaver,  after  Weaver.     X  1. 

Fig.  11.  Nerita(?),  sp.     X  2. 

Fig.  12.  Nerita(?)  biangulata,  n.  sp.     X  3. 


[168] 


UNIV.   CALIF.   PUBL.   BULL.   DEPT.   GEOL.  [DICKERSON]   VOL.  8,  PL   12 


12 


10 


2a 


4a 


•4b 


EXPLANATION  OF  PLATE  13 

Fauna  of  Martinez  Eocene 
Fig.  1.     Architectonica,  sp.     X  1. 

Fig.  2a.  Architectonica  tuberculata  Weaver,  after  Weaver.     X  1. 
Fig.  2b.  Architectonica  tuberculata  Weaver.    Detail.     X  6. 
Fig.  3a.  Natica  (Gyrodes)  lineata,  n.  sp.     XI. 

Fig.  35.  Natica  (Gyrodes),  sp.     X  1. 

A  common  but  poorly  preserved  form  in  the  Martinez. 

Fig.  4a.  Amauropsis  martinezensis,  n.  sp.     XI. 

A  form  which  is  common  in  the  middle  zone  of  the  Martinez.  It 
appears  to  be  intermediate  between  A.  oviformis  of  the  Chico  and 
A.  alveata  of  the  Tejon. 

Fig.  4b.  Amauropsis  martinezensis,  n.  sp.     X  1. 

Fig.  5.     Lunatia  hornii  Gabb.    X  1. 

Kange  of  this  species  is  Tejon  and  Martinez. 

Fig.  6a.  Lunatia  cf.  nuciformis  Gabb.     X  3. 
Fig.  6b.  Lunatia  cf.  nuciformis  Gabb.     X  3. 

Fig.  7.     Xenophora  zitteli  Weaver,  after  Weaver.     X  1. 

A  form  which  is  restricted  to  the  middle  or  Trochocyathus  zitteli 
and  the  lowermost  or  Meretrix  dalli  zones  of  the  Martinez. 

Fig.  8.     Turritella  clarlci,  n.  sp.     X  2. 

Fig.  9a.  Turritella  infragranulata  Gabb.     X  2. 

The  figured  specimen  is  from  the  Martinez  of  the  Santa  Ana 
Mountains. 

Fig.    9&.  Turritella  infragranulata.     X  2. 

Fig.  10.     Turritella  martinezensis  Gabb.     X  1. 

This  form  was  found  in  Martinez  strata  near  Eock  Creek,  Los 
Angeles  County,  California. 


[170] 


UNIV.   CALIF.   PUBL.   BULL.   DEPT.  GEOL.  [DICKERSON]   VOL.  8,   PL.  13 


3a 


EXPLANATION  OF  PLATE  14 
Fauna  of  Martinez  Eocene 

Fig.  la.  Turritella  pachecoensis  Stanton.     X  1. 

This  very  characteristic  Turritella  has  been  erroneously  reported 
from  the  Tejon.  It  appears  to  be  wholly  restricted  .to  the  Martinez. 
Eange,  lowermost  to  uppermost  Martinez. 

Fig.  Ifc.  Turritella  pachecoensis  Stanton.     X  1. 

Fig.  Ic.  Turritella  pachecoensis  Stanton.     X  1. 

Nodose  specimen  from  the  Santa  Ana  Mountains. 

Fig.  2.     Cerithium,  sp.     X  2. 
Fig.  3.     Alaria,  sp.     X  1. 
Fig.  4.     Anchura  gabbi,  n.  sp.     X  2. 
Fig.  5.     Anchura  englishi,  n.  sp.     X  3. 
Fig.  6a.  Seraphs(.?)  thompsoni,  n.  sp.     X  3. 
Fig.  6b.  Seraphs(.?)  thompsoni,  n.  sp.     X  3. 
Fig.  la.  Ovula  martini,  n.  sp.     X  2. 
Fig.  7b.  Ovula  martini,  n.  sp.     X  2. 


[172] 


UNIV.   CALIF.    PUBL    BULL.    DEPT.   GEOL. 


[DICKERSON]   VOL.   8,    PL.    14 


7b 


EXPLANATION  OF  PLATE  15 
Fauna  of  Martinez  Eocene 

Fig.    1.     Cypraea  bayerquei  Gabb.     X  1. 
Range,  Tejon  and  Martinez. 

Fig.    2.     Tritonium  martinezensls,  n.  sp.     X  2. 
Fig.    3.     Tritonium  buwaldi,  n.  sp.     X  1. 

Fig.    4.     Brachysphingus  liratus  Gabb.     X  1. 

A  very  easily  identifiable  and  characteristic  Martinez  species. 

Fig.    5.     Turbinella  crassatesta  Gabb.     X  2. 
Fig.    6.     Ficopsis,  sp.     XI. 

Fig.    la.  Urosyca  caudata  Gabb.     X  1. 

This   species   changes   with   increase   in   size.     The   nodes   become 
larger  and  less  numerous  in  large  specimens. 

Fig.    71).  Urosyca  caudata  Gabb.     X  1?. 

Fig.    8.     Urosyca  robusta  Weaver.     X  1. 

From  a  locality  near  Selby  Smelter. 

Fig.    9.     Siphonaliaf?)  lineata  Stanton.     X  1. 
Fig.  10.     Hemifusus  waringi,  n.  sp.     X  2. 

Fig.  11.     Neptunea  mucronata  Gabb.     X  1. 

A  characteristic  Martinez  species. 

Fig.  12.     Neptunea  cretacea  Gabb.     X  1. 


[174] 


UNIV.   CALIF.    PUBL    BULL    DEPT.   GEOL. 


[DICKERSON]   VOL.   8,    PL.    15 


10 


EXPLANATION  OF  PLATE  16 

Fauna  of  Martinez  Eocene 
Fig.    1.     Fusus  aequilateralis  Weaver.     X  2. 

Fig.    2.     Fusus  mathewsonii  Gabb.     X  1. 
Eange  Tejon  and  Martinez. 

Fig.  3.  Fusus  occidentalis  Gabb.     X  1. 

Fig.  4.  Fusus  aratus  Gabb.     X  1. 

Fig.  5.  Fusus  flexuosus  Gabb.     X  2. 

Fig.  6.  Fusus  dumblei,  n.  sp.     X  2. 

Fig.  7.  Olivella  claytonensis,  n.  sp.     X  3. 

Fig.    8a.  Perissolax  tricarnatus  Weaver.     X  1. 

This  species  may  be  only  a  variety  of  P.  blakei  Conrad,  as  it  is 
found  in  the  type  Tejon  along  with  the  bicarnate  form.  The  tricarnate 
form  is  however  the  commoner  in  the  Martinez. 

Fig.    8b.  Perissolax  tricarnatus  Weaver.     X  11 

Fig.    9a.  Turris  louderbacTci,  n.  sp.     X  1. 

Fig.    96.  Turris  louderbaclci,  n.  sp.     XI. 

Fig.  10.     Surcula  merriami,  n.  sp.     X  1. 

Fig.  11.     Surcula  (Surculites)  andersoni,  n.  sp.     X  1. 

Fig.  12.     Surcula  fairbanksi,  n.  sp.     X  1. 

Fig.  13a.  Surcula,  sp.     X  1. 

Fig.  136.  Surcula,  sp.     X  1. 


[176] 


UNIV.   CALIF.   PUBL.   BULL.   DEPT.   GEOL.  [DICKERSON]   VOL.  8,   PL.  16 


8b 


8a 


13.  W    13b  w    12 


EXPLANATION  OF  PLATE  17 

Fauna  of  Martinez  Eocene 
Fig.  1.     Heteroterma  gabbi  Stanton.     X  1. 
Fig.  2.     Actaeon  lawsoni  Weaver.     X  3. 
Fig.  3.     Bullinula  subglobosa  Weaver,  after  Weaver.     X  2. 

Fig.  4a.  Einginella  pinguis  Gabb.     X  2. 

A  species  found  in  the  middle  and  lower  portions  of  the  Martinez. 

Fig.  4b.  Einginella  pinguis  Gabb.     X  2. 
Fig.  5a.  Hercoglossa  merriami,  n.  sp.     XI. 

Fig.  5b.  Hercoglossa  merriami,  n.  sp.     X  1. 

This   species   may  be   related   to   the   eastern    species   Hercoglossa 
(Enclimatoceras)  ulrichi  White. 


[178] 


UNIV.  CALIF.   PUBL.   BULL,   DEPT.  GEOL,  [DICKERSON]  VOL.  8,   PL.   17 


5a 


4a 


5b 


EXPLANATION  OF  PLATE  18 
Fauna  of  Martinez  Eocene 

Fig.  1.     Aturia  mathewsonii  Gabb.     X  1. 

This  cephalopod  occurs  both  in  Martinez  and  Tejon. 

Fig.  2a.  Nautilus  stephensoni,  n.  sp.,  side  view.     X  1. 
Fig.  2b.  Nautilus  stephensoni,  n.  sp.,  back  view.     X  1. 


[180] 


UNIV.   CALIF.    PUBL.    BULL.    DEPT.    GEOL. 


[DICKERSON]   VOL.  8,    PL.    18 


VOLUME  5  —  (Continued}. 

PRICK 


6  Notes  on  Lawsonite,  Columbite,  Beryl,  Barite,  and  Calcite  by 

7  The  Fossil  Fishes  of  California,  with  Supplementary  Notes  on  Other 

S.  ^^J^^  5c 

9    Berito^VS^^^^  ™th       5c 

Chemical  Analysis  by  Walter  C.  Blasdale  .....  .....  ------"-"•  ........  •••-  15 


* 

16    Str^gra^nV  a^^ala^io^-S-Se^nPaSo-  Fiction  in  Middle  California,     ^ 


20    Ths  15. 


23. 

ey  ,OC 


by 


28  Thbery        neen-  Asia'and  North  America,  by     ^ 

29  Eoian?kun7^-the-IaTe--TertiarFBeds-  at'  Virgin  "Yailey  and  Thousand  Creek,     ^ 

SO.  WaNd1nf  B',rbdl  ^t^t^^"^^"^Tof]^^  ^ 

Holmes  Miller  ..................................................... 

VOLUME  6. 


Nevada,  by  John  C.  Merriam     Part  I--^.^.0PC      1?0^  ""  25c 

„, 

•- 

7.  A  CoUecTon  of  Mammalian  Eemains  from  Tertiary  Beds  on  the  Mohave  Desert, 

by  John,  C.  Merriam.  10c 

8   The  8?r°ati£$J  ^^  ^^^''ot'^'^^'^^^'^^  Chic°      5c 


. 

1?: 


A 
13    Note"™  tne"EeWionships-of-tne''Marine-Saurian'Fanna  DeBCribed_from  the  Triassic 

c. 


Nna.  13  and  14  in  one  cover 


VOLUME  6—  (Continued). 

PRICE 
].".   Notes  on  the  Later  Cenozoic  History  of  the  Mohave  Desert  Eegion  in  Southeastern 

California,  by  Charles  Laurence^Baker  .~>0c 

Hi.   Avifauna  of  the  Pleistocene  Cave  Deposits  of  California,  by  Loye  Holmes  Miller  ....  15c 

il  Beaver  from  the  Kettlernan  Hills,  California,  by  Louise  Kellogg  ."5c 

us  Desmostylus  of  Marsh,  by  John  C.  Merriam  10c 

19.  The  Elastic-Rebound  Theory  of  Earthquakes,  by  Harry  Fielding  Reid  L!.~>C 

VOLUME  7. 

1.  The  Minerals  of  Tonopah,  Nevada,  by  Arthur  S.  Eakle  25e 

•2.   Peeudostratification  in  Santa  Barbara  County,  California,  by  George  Davis  Louder- 
back 20c 

;!.    Recent  Discoveries  of  Carnivora  in  the  Pleistocene  of  Rancho  La  Brea,  by  John  C. 

Merriam    oc 

4.  The  Neocene  Section  at  Kirker  Pass  on  the  North  Side  of  Mount  Diablo,  by  Bruee 

L.   Clark  .". ].lc 

5.  Contributions  to  Avian  Palaeontology  from  the  Pacific  Coast  of  North  America,  by 

Loye  Holmes  Miller  60c 

6.  Physiography  and  Structure  of  the  Western  El  Paso  Range  and  the  Southern  Sierra 

Nevada,  by  Charles  Laurence  Baker  v 30c 

7.  Fauna  from  the  Type  Locality  of  the  Monterey  Series  in  California,  by  Bruce  Martin.  lOc 

8.  Pleistocene  Rodents  of  California,  by  Louise  Kellogg  15e 

9.  Tapir  Remains  from  Late  Cenozoic  Beds  of  the  Pacific  Coast  Region,  by  John  C. 

Merriam    10c 

10.  The  Monterey  Series  in  California,  by  George  Davis  Louderback 65c 

11.  Supplementary  Notes  on  Fossil  Sharks,  by  David  Starr  Jordan  and  Carl  Hugh  Beal  ...  lOc 

12.  Fauna  of  the  Eocene  at  Marysville  Buttes,  California,  by  Roy  E.  Dickerson  45c 

13.  Notes  on  Scutella  norrisi  and  Scutaster  andersoni,  by  Robert  v\f.  Pack  05c 

14.  The  Skull  and  Dentition  of  a  Camel  from  the  Pleistocene  of  Rancho  La  Brea,  by 

John    C.    Merriam 20c 

15.  The  Petrographic  Designation  of  Alluvial  Fan  Formations,  by  Andrew  C.  Lawson....     lOc 

16.  A  Peculiar  Horn  or  Antler  from  the  Mohave  Miocene  of  California,  by  John  C.  Mer- 

riam          r,c 

17.  Nothrotherium   and    Me-alonyx   from  the  Pleistocene   of   Southern   California,   by 

rer    Stock    ,_* *..     15c 

•  n  the  Ganid  (ieiius  Tephrocyon,  by  John  C.  Merriam  Me 

lU.    Vertebrate  Fauna  of  the  Orindan  and  Siestan  Beds  in  Middle  California,  by  John 

( '.    M  rrriam    .; lOc 

-".   Beeenl   <  >i>s«>rvations  on  the  Mode  of  Accumulation  of  the  Pleistocene  Bone  Deposits 

of  Rancho  La  Brea,  by  Reginald  C.  Stoner  lOc 

21.  Preliminary  Report  on  the  Horses  of  Rancho  La  Brea,  by  John  C.  Merriam  I'lir 

22.  New  Anchitheriine  Horses  from  the  Tertiary  of  the  Great  Basin  Area,  by  John  C. 

Merriam    15C 

23.  New  Protohippnic  Eorses  from  Tertiary  Beds  on  the  Western  Border  of  the  Mohave 

Desert,  by  .John  C.  Merriam :>(- 

24.  Pleistocene  Beds   at   Manix   in   the   Eastern   Mohave   Desert   Region,   by  John    1*. 

Hu  wah  la    ;_'.-„. 

25.  The  Problem  of  Aquatic  Adaptation  in  the  Carnivora,  as  Illustrated  in  the  Oste- 

ology and  Evolution  of  the  Sea-Otter,  by  Walter  P.  Taylor  30c 

VOLUME  8. 

1.  Is  the  Boulder  "Batholith"  a  Laccolith?     A  Problem  in  Ore-Genesis,  by  Andrew 

C.  Lawson  .: I_TM 

2.  Note  on  the  Faunal  Zones  of  the  Tejon  Group,  by  Roy  E.  Dickerson  K)c 

3.  Teelh  of  a  Cestraciont  Shark  from  the  Upper  Triassic   of  Northern   California,  by 

I  laiohl  ( '.  Bryant  : .",,- 

4.  Bird    KVrnains  from   flic   I'h-isl  oc<-m>  of  San    I'rdro,  ( 'a  li  forma,  hv    Love    llnlmrs   Miller.      l<lc 

5.  Tertiary  Echinoids  of  the  Carri/o  Gl b   K,  -ion  in  the  Colorado  Desert,  by  William 

S.    \\  .    Kew    20c 

<').    Fauna  of  flu-  Martine/   BOC6H6  ft'  California,  by   K'oy    Kni.-st    Dickerson  $1.1'.") 


NON-CIRCULATING  BOOK 


U.U.  BbKK 


CD3 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


